From America's Test Kitchen Season 2: Steak Frites
Efforts to re-create restaurant-style fries at home have always disappointed,with fries that were greasy or droopy or burnt on the outside and raw on the inside. We wanted to find a recipe and method for the home cook that would rival those cooked by professionals—crunchy fries with deep potato flavor.
As we found in developing our recipe for Steak Fries (page 185), russet potatoes were preferred for their dense texture and hearty flavor. Because these are starchy potatoes, it was important to rinse the starch off the surface after cutting the potatoes into fries. To achieve evenly cooked fries, we first refrigerated the cut potatoes in a bowl of ice water for at least 30 minutes and then took a double-fry approach. During the first fry, because the potatoes are nearly frozen, the potatoes can cook long and slow, which ensures a soft, rich-tasting interior. A quick second fry at a higher temperature crisped and colored the exterior. We used peanut oil for frying but felt our fries lacked the flavor imparted by lard. A little strained bacon grease gave our fries a touch of meaty flavor just like those found in our favorite restaurant fries.
For those who like it, flavoring the oil with a few tablespoons of bacon grease adds a subtle, meaty flavor to the fries. Their texture, however, is not affected if the bacon grease is omitted. Once you’ve peeled the potatoes, you can use a mandolin or V-slicer, rather than cut them by hand. To prepare steak fries, cut the potatoes one-third-inch to one-half-inch thick, and increase the cooking time to ten to twelve minutes during the initial frying and just a few seconds longer in the final fry. Idaho potatoes are also named "russet" or "Burbank".