Put the chicken in ketchup, I learned this trick at a 5-star restaurant

Ingredients:
1 chicken breast
3 kg of ketchup
5 medium potatoes
1 tablespoon of unsalted butter
1 teaspoon of salt
100 g of grated Parmesan cheese
2 garlic cloves
1 sprig of rosemary
1 pinch of black pepper
1 pinch of chimichurri