Heat the oven: Set a rack in the upper middle of the oven and heat the oven to 425°F. Set out a 10-inch oven-safe skillet and a medium saucepan.

Shred the Fontina and grate the Parmesan if needed. Keep them separate because half of the Fontina goes into the polenta and the rest goes on top.

Start the bean filling: Pour the olive oil into the skillet and heat it over medium heat. When the oil looks loose and shiny, add the onion.

Add 1/2 teaspoon of the salt to the skillet. Cook the onion for 5 to 6 minutes, stirring now and then, until it is soft and lightly golden.

Add the garlic, tomato paste, oregano, and black pepper to the skillet. Stir for 1 minute, until the tomato paste darkens a little and the garlic smells fragrant.

Pour the crushed tomatoes and 1 cup of the vegetable broth into the skillet. Stir well and bring the mixture to a gentle simmer.

Add the cannellini beans to the skillet. Simmer for 5 minutes, stirring once or twice, so the beans warm through and the sauce thickens slightly.

Add the chopped kale to the skillet a handful at a time. Stir each handful into the hot sauce until it starts to wilt, then add the next handful.

Cook the kale for 2 to 3 minutes, until it is wilted and tender but still bright. Taste the filling and add a little more salt or pepper if it needs it, then turn off the heat.

Cook the polenta: Pour the remaining 2 cups of vegetable broth into the saucepan and bring it to a boil over medium-high heat. Add the remaining 1/2 teaspoon salt.

Slowly whisk the polenta into the boiling broth. Reduce the heat to low and cook for 3 to 5 minutes, whisking often, until the polenta is thick but still soft enough to spread.

Stir the Parmesan and half of the shredded Fontina into the saucepan of polenta. Stir until the cheese melts, then taste and add a little black pepper.