Start by bringing a large pot of salted water to a vigorous boil over high heat. Once boiling, add the penne pasta and cook according to the package instructions until al dente, usually about 8-10 minutes. Stir occasionally, then reserve 1/4 cup of the starchy pasta water before draining and set aside.

In a spacious skillet, heat 2 tablespoons of olive oil over medium heat until shimmering. Add the chopped onion and sauté for about 5 minutes until translucent and slightly golden. Add minced garlic and sauté for another minute.

Transfer the sautéed onion and garlic into a blender along with the roasted red peppers and cottage cheese or yogurt. Blend on high speed until completely smooth and creamy, approximately 1-2 minutes.

Pour the blended sauce back into the skillet over medium-low heat. Season with salt, black pepper, and chili flakes to taste. Allow to simmer gently for 5-7 minutes, adding reserved pasta water if too thick.

Add the drained penne pasta directly into the skillet and toss in the creamy sauce until well coated.

Plate the creamy pasta while hot, garnishing with freshly grated Parmesan cheese and chopped parsley.