Adapted from Serious Eats. The Serious Eats version of the recipe is itself derived from Alice Waters' Chez Panisse Vegetables.
2 14-oz cans cannellini beans, drained and rinsed
2 1/2 cups chicken stock or water
1 large bunch hearty greens, such as kale, chard, or mustard greens
4 cloves garlic
3 tablespoons olive oil
1/2 teaspoon dried rosemary
1/2 cup grated Parmigiano-Reggiano
Salt and pepper to taste
Simmer beans in stock or water until softened.
Meanwhile heat oil in a large skillet. Saute garlic over medium-low heat until straw-colored, adding rosemary and a pinch of salt toward the end.
Remove about 1/2 cup of stock or water from the beans. Set aside. Add beans and the remaining cooking liquid to the skillet with the garlic. Smash some beans with a muddler or the back for a fork, to produce a thicker texture. Typically we smash about 1/5 the beans.
Add greens to skillet and cook at low heat until wilted. Add reserved cooking water to maintain a stew-like consistency.
Stir in Parmesan just before serving.