Cook the macaroni in boiling salted water for 8-9 minutes. Add peas for the last 2 minutes. In the meantime wash and dry the tomatoes and possibly cut them in half. Cut ham into cubes. Drain the pasta, quench and drain. Whisk milk and eggs.
Season with salt, pepper and nutmeg. Grease an ovenproof dish (26 cm Ø). Layer macaroni, ham cubes and vegetables in it in a circle. Pour egg milk evenly over it. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 35-40 minutes