Fondue au Gruyere

This is a recipe from the Julia Child cookbook. It's amazing! I love serving it in my fondue pot with Easy French Bread, steamed veggies, lil smokies, and roasted potatoes. This is great at parties, brunches, whenever.

2 1/2 T. butter
3 T. flour
1 1/2 c. boiling milk or cream
1/2 t. salt
1/8 t. pepper
Pinch nutmeg
Pinch cayenne pepper
1 egg yolk
4 ounces coarsely grated Swiss cheese or a combination of Swiss and Parmesan (This needs to be good-quality cheese, not the nasty Walmart brand!)
2 T. butter

Cook the 2 1/2 T butter and flour slowly together in a saucepan for 2 minutes without coloring. Off heat, whisk in boiling milk or cream, then the seasonings. Bring to a boil, stirring, for one minute. Sauce should be very thick. Remove sauce from heat. Place egg yolk in center of sauce and beat it immediately with a wire whisk. Beat for a minute to let it cool slightly, then beat in the cheese, and then 2 T. butter. If not used immediately, dot the top of the sauce with butter to prevent a skin from forming.