Drain the tomato peppers well, reserving 100 ml of the broth.
Place the Kasseler slices in an ovenproof dish.
Slice the mushrooms. Heat a pan over medium-high heat and cook the mushrooms for about 5 minutes until golden. Season with salt and pepper. Spread the cooked mushrooms over the Kasseler slices.
In a bowl, mix the chilli sauce, whipped cream, and the reserved 100 ml of tomato pepper broth. Pour this mixture over the ingredients in the baking dish.
Bake in a preheated oven at 180°C (350°F) for about 30 minutes.
Remove from the oven. Spread the grated cheese evenly over the top. Return to the oven and bake for another 10 minutes until the cheese is melted.