Romanesco Broccoli and Cauliflower Pasta

1 tablespoon olive oil
2 tablespoons butter
1 large onion, chopped
2 large cloves garlic, finely chopped
salt and pepper
1 cup chicken broth
1 head broccoli and cauliflower, cut into florets
1/2 teaspoon red pepper flakes
1 teaspoon lemon zest
1 box rigatoni
1 cup ricotta cheese
1 tablespoon thyme
1/2 cup Parmesan cheese

Heat olive oil in a large sauce pan over medium heat. Add butter and melt. Add onion and garlic to pan and season with salt and pepper. Stir and cook for 8-10 minutes to soften.

Add broth to pan, stir for one minute. Add broccoli and cauliflower over onions and add crushed red pepper, lemon zest to the pan. Cover and cook 10 minutes.

Drop pasta in boiling water after the veggies have been cooking 3-4 minutes. Cook pasta al dente. Add ladleful of starchy pasta cooking water over the veggies. Drain pasta and toss it into the pot with sauce. Stir in ricotta cheese, thyme and Parmesan cheese. Season with salt and pepper to taste.