Cook the Pasta: Bring a large pot of salted water to a boil. Add pasta and cook until al dente, about 8-10 minutes. Reserve 1 cup of pasta water, then drain.

Sauté the Aromatics: In a skillet, heat olive oil over medium heat. Sauté diced onion and minced garlic for 5-7 minutes until soft. Season with salt, pepper, and red pepper flakes.

Blend the Sauce: Transfer sautéed mixture to a blender, add white beans and ½ cup pasta water. Blend until smooth.

Adjust Sauce Consistency: Pour sauce back into skillet, add remaining pasta water gradually, stirring until creamy. Warm for 3-5 minutes and adjust seasoning.

Combine Pasta and Sauce: Add the cooked pasta to the skillet, toss in the sauce and cook for an additional 2 minutes.

Serve and Garnish: Transfer pasta to plates and garnish with parsley. Serve hot.