Cut the potatoes into small pieces/cubes. Pour water into a pot, add a pinch of salt, and when the water boils, put the potatoes into the pot and cook for about 15-20 minutes until the potatoes are tender. If you can easily pierce them with a fork, they’re done. Drain the potatoes and wait for about 10 minutes, then transfer them to a larger bowl and add room temperature butter and pour in milk. Using a potato masher, mash everything well to create a smooth potato puree. (Meanwhile, while you ‘wait for the potatoes,’ start preparing the sauce).
Grate some Cheddar cheese using a fine grater and add it to mashed potatoes. Also, add Dijon mustard, salt, and pepper to taste. I added about 3/4 teaspoon of salt and half a teaspoon of pepper, but add as much as you like. Mix everything well and set aside the potato and cheese mash aside.
Slice your favorite selected sausage into thin rounds. Meanwhile, finely chop large onions into thin strips. Heat some oil in a pan and add the sausage. Sauté it for about 6-7 minutes over low/medium heat until it browns nicely. After this time, set the sausage aside on a separate plate. If necessary, add a bit more oil to the same pan and toss in the chopped onions. Mix the onions well with those dark, brown “leftovers” from frying the sausage. We’ll lightly caramelize the onions. Start by sautéing them over medium heat for 3 minutes, then reduce the heat and continue sautéing for about 15-20 minutes, stirring occasionally. Towards the end of cooking, season the onions with salt and pepper.
Afterward, add two tablespoons of butter to the onions and mix. When the butter melts, sprinkle the onions with wheat flour, stir it, and sauté the onion-flour mixture for about half a minute. Then pour white wine into the pan – while pouring the wine, keep stirring the onions to prevent flour lumps from forming; this will create a kind of thick paste. Next, pour in the broth, also stirring constantly to ensure no flour lumps form. Add soy sauce, thyme, marjoram, or Italian Herbs, and mix everything well. Once the sauce comes to a boil, reduce the heat slightly and simmer the sauce for about 15 minutes, stirring occasionally. After this time, the sauce should have thickened significantly.
Once the sauce is ready, add the previously set aside sausage to it and mix. Then transfer the sauce to a baking dish, spreading it evenly. On top, spoon the previously prepared mashed potatoes, for example, using a spoon. The entire sauce should be covered by the mashed potatoes. Do not press the mashed potatoes too hard into the sauce – a gentle pressing with a spoon is sufficient. Now, using a fork, create small “rough peaks” that will lightly and nicely brown in the oven.
Place the casserole in a preheated oven set to 200 degrees Celsius (390 degrees Fahrenheit) and bake for 20–25 minutes. After taking it out of the oven, wait a few minutes before you start eating It’s worth serving with your favorite salad or coleslaw, for example, made from white cabbage. Enjoy! ♥