One-Pan Tomato Spinach Tortellini

(220g) uncooked tortellini (we used ricotta cheese stuffed tortellini)

olive oil

medium onion, minced

Roma tomatoes, diced

fresh spinach, roughly chopped

garlic cloves, minced

Salt and fresh cracked pepper

vegetable stock

Crushed red chili pepper flakes

Grated parmesan cheese, for garnish