Polenta and Cannellini Beans in Tomato Sauce

Place tomatoes with their juices in a large cup/bowl and use a hand mixer to puree them. Heat 1 tablespoon oil in a large broiler-safe skillet over medium-high. Add onion; cook, stirring often, until golden. Add oregano and salt and cook, stirring occasionally. Add crushed tomatoes simmer, stirring occasionally, for 15 minutes.
Add beans to skillet, simmer for a few minutes adjust herbs and salt to taste. Meanwhile, preheat broiler with oven rack 6 inches from heat.
Nestle polenta slices into sauce, overlapping slightly. Spray the polenta with avocado or olive oil. Transfer skillet to oven; broil until bubbling and browned in spots, 4 to 6 minutes. Top with finely chopped basil.