Wash the parsley, dab dry, put something aside for garnishing. Pluck the leaves from the rest and chop them coarsely. Peel and finely chop the onion. Heat the oil in a large, coated pan.
Fry the minced meat for 7-8 minutes until crumbly. Meanwhile bring 500 ml water and 1 teaspoon of salt to the boil, remove from the heat and stir in the mashed potato powder with a whisk. Let it cool down briefly, fold in parsley and season to taste with salt and pepper.
Add the Mexico mix, onion and tomato paste to the mince, fry for 2-3 minutes, season with salt and pepper. Deglaze with broth. Layer the minced meat mixture in an ovenproof dish, add mashed potatoes as a topping.
Sprinkle with cheese and gratinate under the grill of the oven for 2-3 minutes. Garnish with parsley.