Potato Starch v. Potato Flour
Good morning, all! So, for my Valentine, I am making David Tanis's (NYT City Kitchen) Lobster Pot Pie . He writes: "Regarding the sauce, many recipes call for a flour-thickened, milk-based sauce [...] Here it is made with half-and-half, lightly cooked leeks and celery, a touch of potato starch and a dollop of crème fraîche. The difference is palpable." Not that I am going to be palpating anything lobster related, but at the store, I was confronted by Bob's Red Mill Potato Starch and Bob's Red Mill Potato Flour. I wanted to buy/store just one container, but was intrigued by the potato flour and an adjunct to my bread making. I ended up buying the potato starch because I'll bet David Tanis knows more than I do. But I was wondering, are the two interchangeable or is the starch more sauce friendly and the flour more for baked goods?
Thanks for your help.