Cut the tomatoes across in half, hollow them out slightly, and season with salt and pepper.
Blanch carrot, cucumber, cauliflower, and broccoli. Marinate carrots, cucumbers, cauliflower, and mushrooms separately in vinaigrette for 1 to 2 hours and drain.
Marinate broccoli for 5 minutes and drain. Arrange vegetables in tomato halves.
Refrigerate and serve.