Saute onions in butter in a sauce pan until translucent. Spread into unbaked pie shell. Top with diced ham, then with Swiss cheese. Beat together eggs, milk, salt, pepper, and nutmeg. Mix well. Pour over cheese. Bake in a preheated 350 degree oven for 30 minutes*, until a knife inserted halfway between center and edge comes out clean. Let sit on a wire rack for 5-10 minutes before slicing and serving.
*I baked my quiche a little over an hour in order for it to be done. Next time, I think I’ll try adding another egg and see what happens.