Place puff pastry slices next to each other and defrost at room temperature. Peel, wash and slice the carrots. Clean the cauliflower and broccoli and cut into florets.
Cook the cauliflower in salted water for about 8 minutes. Add broccoli and carrots after 3 minutes. Drain vegetables and let them drain well. Wash and clean the tomatoes. Grate cheese. Mix eggs, 50 g cheese and milk and season with salt, pepper and nutmeg.
Place the puff pastry slices on top of each other and roll out round (approx. 30 cm Ø), fold in any protruding edges. Line a greased tart mould with lift-off base (26 cm Ø) with the dough. Wrap protruding edges or corners inwards.
Arrange the vegetables in the tart. Add egg milk and sprinkle with 50 g cheese. Bake the vegetable cake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 1 hour. If the surface becomes too dark, cover with aluminium foil.