Now roast your pieces. I tossed them with olive oil, salt and pepper. I decided to roast some potatoes too that could be the filling for the second tart. Just a couple of russets, peeled and cubed. The squash and potatotes can share a sheet pan, roast them in a 400 degree oven, start checking them at 20 minutes, roast until browned and tender. Try not to eat them all as they cool, you need them for your tart! While these were roasting I carmelized an onion, this was a purple one because it is what I had, you could do white, brown, or even shallots. As the squash cooled, I grabbed some baby spinach. Yes it was from a bag. I have none growing right now! I threw that baby spinach in the pan with the hot, carmelized onions and tossed it until it wilted a bit, then I added the butternut squash to the mix.
Now for the crusts. If you made your crust way in advanced, like the day before, or the week before and it's been sitting in the back of your fridge waiting for that inspiration, pull it out and let it warm up. You wouldn't wanted to be rolled on when you were all cold and stiff would you? Roll the crust out on a well floured counter, or for the sake of less clean up, roll it out directly on your sheet pan. I abhor these "airbake" cookie sheets for baking or roasting, but for a tart they work perfectly. I use the word tart loosely, I am too busy and well, lazy, to make a proper tart for a weeknight dinner, instead I opt for a lovely alternative I call free form. Once the crust is rolled out, pile the squash, spinach, onion mixture in the center, grate some cheese over the top. I used gran padano, then fold up the sides, leaving the filling peeking out the center. Pop it in the oven and bake for about 30 minutes, until the crust is nice and browned. Slice and serve. If you are wondering about the russets, they too got put in a crust, topped with mozzarella cheese. Equally delicious, but not as colorful.