Remove large center ribs and stems from the kale. Cut crosswise into ½-inch slices. Rinse and drain (kale will still have water clinging to leaves).

Heat 2 tablespoons of the olive oil in a heavy large pot over medium heat. Add the chopped onion and cook until soft and translucent, stirring occasionally, about 6 minutes. 

Add the sliced garlic and pepper flakes and sprinkle with salt. Continue cooking and occasionally stirring the onion/garlic mixture until the onions are golden brown, about 5 minutes.

Add the kale and remaining olive oil and toss until wilted, about 3 minutes. Cover pot and reduce heat to medium-low. Continue cooking until kale is very tender, stirring occasionally and adding water by teaspoonfuls if dry, about 20 minutes. 

Gently stir in the cannellini beans to heat.

Meanwhile, cook the pasta in medium pot of boiling salted water until tender but still firm to the bite, stirring occasionally (follow manufacturer’s directions, checking a few minutes before total time).

Reserve ½ cup cooking liquid, and drain pasta. 

Add pasta to the kale mixture in the pot. Add the zest and lemon juice and 3 tablespoons cooking liquid; toss to combine, adding more liquid by tablespoonfuls if dry.

Sprinkle pasta with grated Parmesan cheese and serve.