To blanch the potatoes, first set up a baking tray with paper towels or a clean kitchen cloth. Then gather a spider and make sure the oil is at the correct temperature.
Dry a handful of potatoes with another clean kitchen cloth. The potatoes must be dry so they don’t splatter once they hit the oil. Working in small batches, place the potatoes onto the spider and gently lower them into the oil. Blanch for about 1 1/2 to 2 minutes or just until softened slightly. You might also want to use a timer so you can time each batch. This will ensure that all of the potatoes cook evenly.
When blanching the potatoes, they should not turn golden at all. When they are ready, remove them from the oil and place onto the baking tray. The potatoes should be just cooked through but still have some resistance when you squish them. Continue to blanch the potatoes in batches, making sure the oil has returned to the proper blanching temperature each time before adding more. If the oil is too cold, the potatoes will absorb too much oil and be greasy.
Once all of the potatoes have been blanched, arrange them on the tray so they don’t stick together. Then chill in the refrigerator for at least an hour to ensure they are nice and cold. However, they can be stored for up to one day before cooking. Chilling the potatoes allows them to dry and, therefore, brown better once they are returned to the oil for the final cooking.