In a saute pan on medium high heat, saute the onions in the olive oil until sofrt, about 15 minutes. When they just start to brown, add the minced garlic. Continue cooking for about 2 or 3 minutes, then add the diced tomatoes and a teaspoon of kosher salt, all the pink peppercorns, and 1 tablespoon of herbs de provence. Lower the heat to simmer, stir to combine, and cook for about 30 minutes.
Add the chopped roasted red pepper, stir to combine, and let the sauce simmer on the lowest setting for as long as you can. I let mine bubble away for about 2 hours, stirring every so often to prevent burning. I was busy doing chores while this cooked.
Mandoline all the squash, eggplant, and roma tomatoes in the same thickness, somewhere around a quarter inch thick. Cover the bottom of a large casserole dish with some of the sauce. Arrange the vegetables over the top. I did a zucchini, crookneck, eggplant, tomato arrangement.
Preheat the oven to 250. Lightly spray the finished casserole with cooking spray. I use the Kirkland brand because it's non GMO, etc, etc. Sprinkle 1 tablespoon of herbs de provence over all the vegetables. Cover the casserole dish with parchment paper and place in the center of the oven. Bake for 2 hours or 1 hour on convect.
Meanwhile, take 1/4 cup of the pepper and tomato sauce and whisk it with the 2 tablespoons of olive oil, a pinch of salt, and 2 tablespoons of really good balsamic vinegar. Pull the casserole out, brush it with the vinaigrette, and return it to the oven uncovered for about 30 minutes or 15 minutes on convect. The leftover sauce can be used to make an amazing salad dressing or a dynamite sauce on a pizza.