Prepare ingredients for the recipe.
Saute brats on all sides until they are golden brown. Set aside to let the brats to cool.
Dice mushrooms into quarter, saute them in a same skillet as where you cooked brats. Remove from the seat and place it in a large bowl.
Dice potatoes into small pieces. Brown them on a oiled skilled, season with a little bit of salt. Set potatoes aside into the same bowl.
Cut up sausage into rings and cook it on a skillet until the sides get a little more browned. Add them to the same bowl.
Dice bell peppers and green onions into tiny pieces. Stir everything all together. Season with salt to taste.
Stir in cheese with all the ingredients. Place everything together in a baking dish. Cover it with a lid and let it bake at 350F for about 15 minutes.
Remove the lid and bake for another 5 minutes. Serve right away.