Preheat the oven to 100 - 150 ° C. Thinly slice or chop the garlic. Dice the onion and place in a saucepan with the garlic and sweat until translucent. Add the tomatoes and reduce the heat.
Wash the rocket, then chop it up a little. Add the rocket to the sauce and season with salt, pepper, herbs and olive oil. Now bring the sauce to a boil and then season to taste and add seasoning if necessary.
Remove the sauce from the heat and fry the chicken breast fillet in a pan while cutting the mozzarella into slices. Now place the meat in a baking dish, pour the sauce over it and cover with mozzarella. Garnish with pepper and / or the Italian herbs.
Bake in the preheated oven for approx. 10-15 minutes. The time can vary depending on the desired degree of browning.