Heat the olive oil in a large pan over a medium-high. Add the onion with a pinch of salt and sweat for 8 minutes until soft. This is a great time to add some hidden veg to the sauce, chuck in some finely chopped carrot or pepper for example - it’s all good in the dish.
Add the tomato sauce and beans with their bean stock. Add the oregano, if using, and simmer a little. If the mixture looks too dry or thick, fill the jar of sauce ⅓ with water, give it a shake and throw that in too. Simmer the mixture for 5 minutes until bubbling and hot, then add the spinach and allow to wilt. Turn your grill on to a high setting at this point.
If you’re pan is grill-proof, top the mixture with torn mozzarella pieces, parmesan and any other toppings you want to add. OR, transfer the mixture to a medium sized oven proof wide dish and add all of the toppings.
Grill for 5 minutes or so until golden brown.
Garnish with fresh basil and serve with a fresh green salad and garlic bread.
