Sift flour, nutmeg, salt and pepper in medium bowl.

Beat eggs in a large bowl.

Mix flour mixture, and milk into eggs until smooth.

Let stand 30 minutes.

Chop onion and mushrooms.

Bring large pot of lightly salted water to a boil.

Press noodles through a spätzle press (or cheese grater) into water.

Remove floating spätzle with a slotted spoon and place into large bowl.

Mix 1 1/2 cups cheese into noodles.

Melt butter in large saucepan and add mushrooms. Cook 2 minutes.

Add onions and cook until translucent.

Add spätzle and remaining cheese. Cook 1 minute.

Serve immediately.