1 cup strongly flavored cheese such as Swiss or Gruyère, grated
Instructions
In a mixing bowl, whisk egg and water until well combined; add flour and salt until you get a lump free and a thick, sticky batter; let it rest for 20 minutes.
Meanwhile, cut the onion in half lengthwise and slice it finely into even rings.
Heat oil and butter together in a big pan; add the sliced onion and cook over medium heat for about 10 - 15 minutes or until onions turn golden brown, stirring often; set aside.
In case there is any oil/butter left in the pan, leave it; unless there are black particles from frying the onion; in that case, discard it.
Bring a large pot of salted water to a boil.
Carefully hold a spätzle maker, or a colander/veggie grater with large holes, over the boiling water.
Place about ½ cup of the batter on the spätzle maker/colander and press it into the simmering water using a spatula or the back of a spoon; repeat until all of the batter has been used.
Cook the spätzle for an additional 2 minutes until they all float on the surface; drain.
Put spätzle into the pan where you cooked the onions.
If there is no butter/oil left, add 1 teaspoon butter and heat butter; when melted, add spätzle and cheese.
Stir over medium heat until cheese has melted.
Scatter the caramelized onion over the spätzle and serve.
Notes
If your batter is too thick, and you can't press it through the holes of your colander/veggie grater, you can add 1/4 cup more water to the batter.