Peel and finely chop the onion. Heat the oil in a pan. Add minced meat, crumble with a spatula and fry while turning. Add the onion. Stir in tomato paste and ketchup.
Season to taste with salt, pepper and paprika. Clean and wash the rocket and carefully dab dry. Remove the dough from the package. Unroll the dough roll and separate into predetermined triangles. Cover each triangle with rocket and minced meat.
Divide 3/4 of the cheese between the 6 triangles. Roll up loosely from the narrow side and bend carefully into croissants. Place on a baking tray lined with baking paper. Sprinkle with remaining cheese.
Bake in the preheated oven (electric oven: 200 °C/ gas: level 3) for 12- 15 minutes. In the meantime whisk the egg yolk and cream. Brush the croissants with the mixture about 2 minutes before the end of the baking time. Serve the croissants on a plate with cherry tomatoes and parsley.