Preheat your oven to 425°F (220°C).

In an oven-safe skillet, heat a tablespoon of olive oil over medium heat. Add diced yellow onion and sauté for about 5 minutes until softened and translucent. Stir in minced garlic for an additional minute.

Pour in the whole peeled tomatoes, breaking them up if needed. Add dried oregano, salt, black pepper, and red pepper flakes, and simmer for 10-12 minutes.

Gently fold in the rinsed white beans and cook for an additional 5 minutes.

Remove from heat and sprinkle mozzarella and Parmesan cheese on top. Bake for 10-15 minutes until the cheeses melt and bubble.

Let cool slightly, then garnish with fresh basil or parsley before serving.