Peel and wash the potatoes and cut them lengthwise into slices. Cook for about 10 minutes in boiling salted water. Meanwhile clean the leek, cut it in half lengthwise, wash it and cut it into approx. 5 cm long pieces. Add to the potatoes and cook for another 2 minutes. Drain potatoes and leek on a sieve.
Wash apples and cut them lengthwise into slices. Remove the blossom base. Sprinkle the slices with lemon juice. Wash thyme, dab dry and cut into small twigs. Cut the cheese into 2 cm pieces. Fill apple, leek, potatoes and 2/3 of the thyme into a greased casserole dish. Mix sour cream, cream and egg. Season with salt and pepper and pour over the vegetables. Spread cheese slices on the casserole. Bake in the preheated oven (electric: 200 °C/ gas: level 3) for 30-40 minutes.
Fill apple, leek, potatoes and 2/3 of the thyme into a greased casserole dish. Mix sour cream, cream and egg. Season with salt and pepper and pour over the vegetables. Spread cheese slices on the casserole. Bake in the preheated oven (electric: 200 °C/ gas: level 3) for 30-40 minutes. Halve the bacon slices and place them on the casserole after about 20 minutes of baking time. Sprinkle with crushed red berries