Wash the chicken meat and pat dry. Cut one pocket in each. For the filling, finely dice bacon and toast. Leave out the bacon in a hot pan. Add toasted bread, stir in tomato paste and sage.
Season with salt and pepper. Pour the mixture into the chicken fillets and add with wooden skewers. Put the spaetzle in boiling salted water and cook for 12-15 minutes. In the meantime heat up oil in a pan.
Fry the meat for about 10 minutes from both sides. Clean and wash the leek and cut into fine rings. Heat the fat. Steam the leek for 3-5 minutes. Season with salt and pepper. Keep meat warm.
Peel and finely chop the onion. Sauté in frying fat. Add chicken soup and tomatoes and let it boil down a bit. Season sauce with salt and pepper. Drain and drain the spaetzle and mix with the leek.
Season the chicken fillets and arrange on a plate with the leek noodles. Pour a little sauce over it. Remaining sauce extra is enough. Garnish with sage and parsley leaves if desired.