Listen to me and listen good: I am not talking about homemade onion dip. I am talking about a room-temperature jar of the beige, kind of jiggly stuff (1/2 a cup of dip for every 2 pounds of potatoes and 1/2 cup of butter works best). Like mayo, store-bought onion dip is a great emulsifier but, unlike mayo, it brings flavor—creamy, savory, oniony flavor. Somehow, though, the dip manages to be subtle. No one will taste these potatoes and shout “Hey, you put onion dip in these!” They will take a bite, pause, and ask for your secret ingredient. But you’ll never tell.