Alsatian Onion Tart

Alsatian Onion Tart


Soft and creamy onions are surrounded by a buttery crust, in this classic Alsatian French tart.
  • Serves: 6 to 8
  • Active Time: 1 hr 30 mins
  • Total Time: 2 hrs 30 mins
  • Views: 38,801
  • Success Rating: 91% (?)
    0% - I fed it to the dog


Step 1: Making and Rolling the Dough

• 10 tbsp cold, unsalted butter
• 5 tbsp ice cold water
• 1 2/3 cups all-purpose flour
• 1 pinch table salt


Make sure all of your ingredients are cold before making the dough. Add the salt to the flour and grate in the butter. Coat the butter with the flour by lightly tossing. Add the water, a bit at a time to form the dough. Lightly bring the dough together. Wrap and let rest in the refrigerator for approximately 45 minutes.

Roll the dough out to 1/4" -inch thickness. Transfer to a 9" -inch tart pan. Shape and place into the freezer for 20-30 minutes (or chill in the fridge for about an hour) until firm.

Step 2: Preparing the Onions & Pre-Baking Tart

• 7 cups onions
• 1/4 cup vegetable oil
• 2 pinches table salt
• 2 tbsp all-purpose flour
• 1/2 cup milk
• 1/2 tsp table salt
• 1/8 tsp white pepper


Preheat your oven to 425° degrees Fahrenheit.

Thinly slice the onions. Heat a large fry pan over high heat. Add the oil and onions and then reduce the heat to medium. Cover and let sweat for about 5 to 10 minutes, or until soft and melted. Remove the lid and turn the heat to medium. Let this cook for another 15 minutes or so, stirring occasionally. Once all of the moisture has evaporated, caramelization will occur rather quickly. Add the salt and make sure to stir every 20 seconds or so to obtain even coloring.

Off the heat, deglaze with a bit of water, and scrape to clean the bottom of the pan. Sprinkle in the flour and then add the milk. Stir to combine. Season with the salt and white pepper and set aside to cool.

Poke holes into the dough and par-bake the shell.

Step 3: Baking the Tart


To finish the tart, turn the heat down to 350° degrees Fahrenheit. Taste the mixture for seasoning. Place it into the tart shell and spread it out evenly.

Bake for approximately 15 minutes, or until the top sets and the filling binds with the sides of the dough. Let cool for a few minutes before removing from the pan. Slice and serve.

Chef's Notes

Don’t throw out left over dough. It will lose a bit of flakiness because it has been handled, but it’s still ok to use. Use it over the next couple of days, or freeze it for up to one month.


  • Mark D
    Mark D
    When baking blind I prefer to use ceramic beads (available from good supply shops) as they combine high mass together with super heat conductivity. Heston Blumenthal uses old coins; which I find totally unhygenic. Yuk.
  • Greg S
    Greg S
    Anything you buy is unhygienic, too until washed at home. Old coins can be easily cleaned, therefore plenty hygienic, and resourceful. I always encourage the thoughtful reuse of everyday items. Buying unnecessary items is just plain wasteful, adding to your carbon footprint. -cheers
  • Lisa P
    Lisa P
    What would be a good accompaniment to this for a dinner?
  • Joe G Rouxbe Staff
    Joe G
    First two entrees that come to mind for me would be the Beef Tenderloin w/ Peppercorn Sauce (my favorite) or the Roasted Lemon and Cilantro Chicken. I even love the sides paired with these dishes. Anyone else have some ideas?
  • Patrick O
    Patrick O
    No menu is complete without a nice glass of wine to go with it. The sweetness of the caramelized onions and the richness of the butter crust just scream out for an Alsatian Riesling. Bone dry, acidic, with wonderful stone-fruit flavours and mineral components. So here's an idea. Pop and pour the chilled Riesling and have that with a small green salad and the tart, then follow it with Joe's favorite and a nice Cabernet Sauvignon. Now just add desert and you have a perfect menu. Cheers!
  • Keith R
    Keith R
    Very nice rolling pin! I have some dry beans I use when blind baking.
  • Brian M
    Brian M
    I like taking the opportunity to cook during the holidays... especailly when you know you've got a couple of days to tackle things and there always seems to be people around to try your food. This recipe is destined for my smoker or grill... let's see what happens. Yum Brian
  • Alex L
    Alex L
    May i know the name of this type of dough ? Thank
  • Kimberley S Rouxbe Staff
    Kimberley S
    This dough is classified as a flaky dough. All ingredients should be as cold as possible and the dough should not be overworked. The individual parcels of butter make this crust very flaky.
  • Liz S
    Liz S
    The crust is amazing. It took 40 minutes for the onions to caramalize but they were so sweet that my guest asked if I had added sugar. The video is a must to watch to pre-bake the tart shell as the text recipe does not include the 2 steps nor the times. Wonderful recipe that I will be making again for sure.
  • Christophe K Rouxbe Staff
    Christophe K
    Liz, you're right, you can't rush the caramelization of the onions...however you can do that step earlier in the day or even the day before, deglaze with an Alsatian reisling to cut down some of the sweetness...and finish the bottle with your friends.
  • Ashley C
    Ashley C
    I brought this to a family potluck and it was very popular! I didn't have a tart pan, so I had to make do with a pie pan, but it was still perfect. Great recipe!
  • Christophe K Rouxbe Staff
    Christophe K
    Ashley, I'm glad you had success with the onion tart and yes in can be done with a pie plate. However, because of the slopes of a pie plate versus the 90 angles of a removable bottom tart shell, it is imperative to well rest the dough before par baking or it will slide down.
  • Solange C
    Solange C
    Thank you for the recipe. Could you please use weight instead of volume when measuring. It is very difficult to measure 10 tablespoons and you get a mess. Thank you
  • Dawn T Rouxbe Staff
    Dawn T
    While we do know weighing is easier, especially when it comes to baking, it is more common for most people to measure using cups and spoons. You could measure out 1/2 a cup + 2 tablespoons instead of the 10 tbsp. Cheers!
  • Solange C
    Solange C
    I made some meat pies and a blueberry pie using this technique (grating the cold butter). This is such a good idea, I do not know how come people hadn't thought about it earlier. Thank you for the technique.
  • Uzi R
    Uzi R
    Hi, I have guests this weekend but won't have much time to cook the day they arrive, Can I freeze the tart and re-heat? in what stage do you think it would be best?
  • Christophe K Rouxbe Staff
    Christophe K
    Can be done, yet I would avoid it, as the tart freezes "slowly " in your home freezer and especially defrosting you may end up with a soggy pastry. However this pie keeps well for up to 3-4 days in the fridge, to reheat place in a 325°F oven for about 15 minutes - hope this helps.
  • Uzi R
    Uzi R
    Great that is very helpful!
  • Laura C
    Laura C
    I was just wondering the size of the tart pan that was used for this recipe?
  • Dawn T Rouxbe Staff
    Dawn T
    This recipe calls for a 9" tart pan (as per the last paragraph in Step 1). Cheers!
  • Laura C
    Laura C
    Ooops! So sorry. It escaped my eyes... Is there a way to obtain a list of ingredients, preparation time and serving portions in the recipe part of the website, that is, where the text is? I seem to be having trouble finding that info. Perhaps it is because I am so used to the recipe format. I absolutely love your site and recipes. They are very well balanced and exquisite! It is only this details that I am having trouble finding easily. Thanks for your input.
  • Dawn T Rouxbe Staff
    Dawn T
    Not sure if you are referring to the text recipe? If so, then there is a tab and/or button called "Text Recipe". Here you will find all of the ingredients listed. You will also see at the top of the text recipe that "preparation time", "total time", "servings" etc. listed at the top of the page. Hope this helps. Cheers!
  • Laura C
    Laura C
    Thank you Dawn for your reply. I have printed many of the recipes in the site using the tab that reads "Text Recipe" but the info that you mention never comes up in the printed copy. It does not come up either when I look at the recipe in my computer. What I can see are the steps with the ingredients that correspond to the step that it is being explained. But preparation time, serving portions, etc. don't show. I don't know if I am missing something or if it is my web browser (Firefox) and the fact that I am using a Mac. Sometimes that happens.
  • Dawn T Rouxbe Staff
    Dawn T
    Not sure what to say. When we print the recipes, they show up at the top near the title/description. We will contact you offline to try and help you out. Cheers!
  • Laura C
    Laura C
    Dawn, I think I found the trick to have the prep. time and serving portions show up... if I print - or see - the recipe with the tabs that show when I am in the screen where the instructive videos are shown, for some reason, the recipe does not show either the title nor the rest of the information. However, if I go to the main Recipe screen and select "Text" then the recipe prints in a different format, showing all the information that was missing. From now on, I will only print the recipes from this screen. I don't know if this happens to everyone else, but it does to me when I browse your site from my computer. Thank you so much for your feedback.
  • Sheri M
    Sheri M
    I would like to make these as individual tarts. I imagine I would want the pastry to be a bit thinner and would reduct the baking time somewhat. Is this correct? Thanks, Sheri
  • Dawn T Rouxbe Staff
    Dawn T
    You shouldn't necessarily have to make the crust much thinner. It is already quite a delicate crust. As for the baking time, you are correct, you will likely need to reduce the baking time slightly. Just keep an eye on things and remember to look for the signs - golden crust etc. Cheers!
  • Juan jesus R
    Juan jesus R
    Hi, This delicious tart now has become in one of my favorits dishes. Drawbacks? Please be trapped by the dark side of the metric system..... :) Thank you Rouxbe
  • Julie N
    Julie N
    I make these when dinner will be just Michel and myself. I do not really make the crust thinner. Of course, I adjust the carmelized onion recipe. I usually serve this with a roast loin of pork and whatever green is fresh at the farmers market. Just personal favorites. Plus, if I can get a hearty green into Michel verse steak and potatoes (not that I have anything against them, just not every other day) I am very, very happy.
  • David P
    David P
    Hi everyone - I made this tart last weekend with a good degree of success ... the second time around. The first time I did not get the butter in small enough pieces and it melted some holes in the crust. I used the food processor on the second time around and it worked reasonably well, though I found that the butter content was a little high. There was a point both in the blind baking and final baking stages that there was a lot of melted butter around the top and sides of the pan ... to the point that it was overflowing a little. My question is that is this normal? Should I see melting butter around the edge of the tart pan and under it while it's baking? Thanks! Dave
  • Ken R Rouxbe Staff
    Ken R
    Hi David - It sounds like your dough did not incorporate the butter well enough. As the dough cooks, the butter should help cook and swell the starches in the flour to make a dough. Your butter pieces may still be too big. It sounds like your dough is seeping butter or something similar. Try to make the butter pieces smaller and/or reduce your butter to 8Tbs and see if that helps you. Good luck. ~Ken
  • Sarah A
    Sarah A
    This sound like a wonderful dish cannot wait to make it

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