Cook the macaroni in plenty of boiling salted water for about 8 minutes until it bubbles. Drain the tuna. Coarsely chop the tomatoes in the tin with a long knife. Peel onion and cut into small cubes. Peel garlic as well and press it through a garlic press.
Heat the oil in a pot. Sauté onion and garlic in it. Add tomatoes, bring to the boil, add cream and tomato paste, stir in and season to taste with salt and pepper. Put peas into boiling water without defrosting.
After boiling up, cook for 1-2 minutes. Grate cheese finely. Grease a casserole dish and fill it alternately with macaroni, tuna, peas and tomato sauce. Pour cheese over it. Bake in the preheated oven (electric cooker: 200 °C/ gas: level 3) for 35-40 minutes.
Garnish as desired with parsley leaves.