Cook the pasta in plenty of boiling salted water for 8-10 minutes until al dente. Add the peas for the last 3-5 minutes. Drain everything and let drain well.
Drain the tuna. Wash and halve the tomatoes. Whisk eggs and milk. Season with salt, pepper and nutmeg.
Grate the cheese roughly. Pluck tuna into pieces with 2 forks. Spread the pasta and peas in a large greased casserole dish. Add tomatoes and tuna. Pour egg milk over it and sprinkle with cheese.
Bake the casserole in a preheated oven (electric range: 200°C/circulating air: 175°C/gas: level 3) for 40-45 minutes until golden brown. Tomato sauce tastes good with it.