Cook the pasta al dente in plenty of salted water, drain. Thaw the spinach leaves. In the meantime, fry the minced meat with the onion in 2 tablespoons of olive oil and season.
Put the pasta in a large baking dish that has been greased with olive oil. Cut the peppers and tomatoes into pieces. (Put the canned tomatoes over the pasta). Divide the frozen spinach leaves into pieces (chop up fresh spinach leaves). Pour the vegetables over the pasta and mix. Dust the fried minced meat with a little flour.
Prepare a roux from the remaining flour and a little butter, deglaze with water. Pour in the cream, stir and let the processed cheese melt in the cream sauce on low heat. Pour the sauce over the pasta and vegetables and sprinkle with gratin cheese.
Bake in the oven at approx. 160 degrees hot air or 180 degrees top / bottom heat for approx. 30 - 40 minutes. Then serve hot with fresh basil leaves.