Cheesy Baked Chard Rigatoni {gluten-free}

bunches Swiss chard, any color

olive oil

large yellow onion, diced

large garlic cloves, peeled and sliced

dried oregano (or handful basil leaves, chopped)

red pepper flakes

fine sea salt, plus more as needed

black pepper

(about 4 cups / 1 liter, or a little more) canned or jarred tomato passata, puree, or crushed tomatoes (I like a combination of this one, which is extra-thick, and this one)

dry gluten-free rigatoni, penne, or other large tubular pasta (I use this)

/ 225 g) grated dry, whole-milk mozzarella

/ 55 g) lightly packed grated parmesan

best-quality whole-milk ricotta (I like this one)