Spaetzle with Gruyère and Caramelized Onions

INGREDIENTS

3 cups

all-purpose flour

1/4 tsp

freshly grated nutmeg

medium white onion, thinly sliced

large egg

1 1/2 cups

shredded Gruyère cheese (5 ounces)

1 3/4 cups

milk

1 tbsp

unsalted butter, cut into small pieces

Salt and freshly ground pepper

large egg yolks

2 tbsp

peanut oil