Cut the onion into large pieces diagonally. Lemon and apples into slices.
Wash the fish, dry it with a napkin.
Pepper inside and out with black pepper and salt.
Grease a baking sheet with vegetable oil and lay the fish. Sprinkle the fish with thyme, also inside and out. Put lemon slices in the abdomen. Chili pepper can be taken fresh, or dry, ground. Sprinkle the onion around and lay the apple slices. Carefully pour the cider.
Top with salt, pepper and thyme again. Put thin slices of butter on the fish.
Preheat the oven to 200 degrees.
Bake for 35 minutes.