Place the chopped pancetta in the cold Dutch oven and raise the heat to medium heat. Fry the pancetta until golden brown, about 8 minutes once hot. Remove the pancetta from the pan and set aside.
Add 2 tablespoon olive oil to the pot. Add the onions to the pot. Don't stir them. Let them sit for 3 minutes to develop a slight brown char. Then stir them and add in the garlic and the fennel. Saute the garlic for 1-2 minutes. Make a space to add the tomato paste and place it directly on the hot surface, not on top of the onions. Let it sit for 2 minutes, then stir throughout. Add the Calabrian peppers and combine everything.
Pour in the white wine to deglaze the pan. Use a wooden spoon to scrape the bottom of the pan. Add in the cabbage and cover the pot for 20 minutes, opening it every 5 minutes or so to stir. If there is no liquid in the bottom of the pan, add a ¼ cup of water.
Drizzle the cabbage with the last tablespoon of olive oil, and season with salt and pepper. Cover the pot for another 5 minutes.
Once the cabbage is softened, add the cannellini beans and pancetta and stir throughout the dish. Let it sit for 5 minutes until hot. Serve hot!
Notes
Char the onions first to add a sweet and smoky flavor to the dish.
Caramelize the tomato paste directly on the pan for a few minutes to develop the caramelized sweet flavor of the tomato.
Deglaze the pan to scrape the brown bits from the charred onion and caramelized tomato paste on the bottom of the pot.
Depending on the size of the cabbage, the time covered may need to be longer. The cabbage should be fork tender.