Heat a skillet to medium heat, drizzle with olive oil, add onions and garlic. Cook until softened, about 3-4 minutes, stirring often.
Add in lemon zest, lemon juice, beans, salt, pepper and broth.
Bring to a simmer and cook until broth is slightly thickened. Add in parmesan and mix until incorporated and sauce continues to thicken.
Finish with a drizzle of olive oil, fresh parsley and serve alongside crusty bread for dipping.