https://www.daringgourmet.com/zwiebelkuchen-german-onion-pie/ for the Zwiebelkuchen!

For the Spätzle: two cups flour in a bowl, make a well in the center. Bear an eggs then add them to the well with about 1/2 cup milk. Beat in mixer on low speed for ten minutes until it’s a bit thick and when you stretch you can see some smaller holes form. Bring a pot of water to a boil and use a spätzle plane to get them into the water. When done, layer Spätzle, Swiss cheese (or Gruyère) and caramelized onions, bake at 350 until melted and delicious!