serves 4–6; adapted from Kathie Alex and François de Mélogue of SimpleFrenchCooking.com
Bring a large pot of salted water to boil.
Cut the vegetables either in half lengthwise, across the midline, or slice off just the top for smaller round shapes, reserving the caps. Scoop out the flesh of the squash and reserve. If using tomatoes, scoop out and put aside for another use (I keep a freezer bag of fresh tomato trimmings to use later for soups and stews).
Eggplants are good to use, but they need to be roasted for about 30 minutes at 350° before stuffing.
Set out a clean kitchen towel for draining the vegetables after blanching. Blanch the vegetables and transfer cut side down onto the towel to drain.
Heat a splash of olive oil in a frying pan and cook the onion about 5 minutes. Chop the reserved inside flesh and add to the pan and cook a few minutes to soften. Transfer to a mixing bowl.
Add the meats to the pan and cook until crumbled and no longer pink inside. Drain off fat and transfer meat to the mixing bowl. Add the breadcrumbs, Parmesan (if using), chopped garlic and optional fresh herbs (parsley, etc.). Season with herbes de provence, salt, and freshly ground black pepper. Crack in one egg and mix to combine. If it seems dry, add another egg.
Preheat oven to 375°F.
Place drained vegetables in a baking dish and stuff each with filling. Sprinkle with Parmesan (if desired), drizzle with a little olive oil, replace any caps if you have them, and bake for 30 minutes.