Heat oil in a skillet over medium heat. Add onion and cook for 5 minutes. Add in garlic and cook for another 3 minutes.
Add all remaining ingredients to the pot except for the kale and mozzarella cheese. Stir to combine.
Partially mash the beans using a potato masher or jar, I mashed maybe 25% of the beans.
Bring to a gentle simmer, being careful not to let it boil, and cook for 10–15 minutes, stirring occasionally.
Turn heat to low and fold in the kale.
Turn off heat and sprinkle over cheese. Add skillet to oven and bake for 5-7 minutes, until cheese is nice and melty. Top with red pepper flakes and olive oil if using and serve with bread.
Notes
Nutritional information is for ¼ of the recipe which is a regular sized bowl. It is a super filling recipe!