Put all ingredients in a bowl and stir with a hand mixer until the dough starts to bubble. I recommend dough hooks here. The dough should then be extremely sticky if everything went well.
Bring the water with salt to a boil.
Place the dough on a board and then pour it into the water in layers with a knife. (I have a spaetzle maker from T-Ware, it`s a bit easier here because you just have to push the dough through the holes. There are more buttons than spaetzle, but that doesn`t matter in terms of taste.) Finished spaetzle float on the surface of the water and can easily be removed with a slotted spoon. Put the finished spaetzle in the baking dish.
When all the spaetzle dough has been processed, cut the meatloaf into cubes. The size of the cubes does not matter. I often cut these into bite-sized pieces. Fry the Leberkäse evenly in a pan. Peel the onion, cut into small cubes and fry briefly with the Leberkäse until translucent. Then deglaze everything with milk and cream. Season the sauce with nutmeg and, if necessary, salt and pepper.
Pour the Leberkäse and sauce over the spaetzle and mix everything together. Spread the cheese over the pasta. If there is not much sauce, you can now simply tip a little milk on top.
Bake the casserole for approx. 15 minutes in the oven at 200 ° C top / bottom heat. Take the casserole out of the oven and sprinkle with the cut chives.