Bring a large pot of salted water to a rolling boil, add pasta and cook according to package instructions, about 8-10 minutes. Reserve 1 cup pasta water before draining.

Heat olive oil in a skillet over low heat. Add diced onion with a pinch of salt, black pepper, and red pepper flakes. Sauté for about 5 minutes until translucent.

Add minced garlic to the skillet and cook for 1-2 minutes until aromatic and slightly golden.

Blend sautéed onion and garlic with drained white beans and lemon juice, adding reserved pasta water until smooth and creamy.

Return the blended sauce to the skillet, adjusting with more pasta water as needed for desired consistency. Season with salt and pepper.

Add drained pasta to the sauce, tossing thoroughly for about 2 minutes until well-coated.

Plate the pasta, garnish with parsley, serve hot, and enjoy!