Heat olive oil in a wide pot over medium heat. Add the onions and cook for 10–15 minutes, stirring occasionally as they begin to sweat.
Add the sugar and salt to the onions. Continue cooking, adjusting the heat to medium-low as needed, for an additional 20–30 minutes until caramelized. Stir regularly as they cook to prevent burning.
Prepare the sauce:
Season the onions with Italian seasoning, garlic powder, and crushed red pepper. Add the tomatoes and vegetable broth. Bring to a boil. Reduce the heat and simmer, uncovered, for 25–30 minutes until reduced. Continue simmering until the sauce has reduced by almost half. Taste and season.
If desired, blend the sauce until smooth with an immersion blender.
Cook the ravioli:
Bring a large pot of salted water to a boil. Cook the ravioli according to package instructions and then drain. Divide the ravioli between four bowls.
To serve:
Spoon the sauce into shallow bowls and serve the ravioli on top. Garnish with fresh basil leaves, a drizzle of extra virgin olive oil, and a few cracks of black pepper. Enjoy!
Recipe notes
This is meant to be a thinner tomato sauce. If you prefer a thicker sauce, use just two cups of water or vegetable broth.