Notes about the recipe: The first dish I ever made by myself (I think it was from a Kraft booklet my mother had lying around) was, oddly enough, a cheese souffle. I didn't know that souffles were hard to make — and it wasn't. Cheese souffles are simple because of the cheese, which lends body and structure. It was from that recipe that I picked up the trick of adding mustard to melted cheese; you don't taste the mustard, but the cheese tastes more cheesy. A gougere is an irresistible bite-size cheese souffle, best served right out of the oven. Any tasty Swiss-style cheese will do here; fol epi is a young version. You can tell how old a Swiss cheese is by the size of the holes; they get larger as the cheese ages.
Heat the milk and butter in a medium-large saucepan over medium-high heat. When the mixture simmers and the butter is melted, add the flour all at once and stir. Add the salt and pepper. Reduce heat to medium and stir for 1 to 2 minutes to dry the mixture out. Turn off heat and stir a bit more to cool slightly.
Add the eggs 1 at a time, beating well to incorporate each egg before adding the next. Stir in the cheese, mustards, and cayenne and mix until smooth. Transfer the mixture to a pastry bag with a large plain tip.
Pipe the mixture onto to a parchment paper-lined cookie sheet in rows of kisses, about 1- inch in diameter.
Smooth out any bumps with a fingertip dipped in flour.
(The recipe can be made to this point up to 8 hours in advance and refrigerated, or frozen for up to a week. Thaw at room temperature before baking.)
Bake for 10 minutes. Reduce the heat to 375 degrees F and continue baking until golden brown, about 8 to 10 minutes more.