Add the olive oil and butter to a large skillet over medium heat. Allow the butter to melt completely, combining with the olive oil. This will add richness and flavor to the base of your sauce.

Add the minced garlic and finely chopped shallot to the skillet. Cook for 2-3 minutes, stirring frequently, until they become soft and aromatic. Be careful not to brown them; that could make the sauce bitter.

Pour in the milk, followed by the sour cream. Whisk the mixture gently until it’s smooth and starts to heat through. Let it simmer lightly to bring the flavors together but do not let it boil to avoid curdling the sour cream.

Add the grated Parmesan (or Pecorino for a bolder flavor) to the skillet. Stir well until the cheese melts into the sauce, creating a creamy, cohesive texture.

Add salt and black pepper to taste. If you like a bit of heat, sprinkle in a pinch of red pepper flakes. Adjust the seasonings to your preference, tasting as you go.

Add the cooked pasta to the skillet, stirring to coat it evenly with the sauce. Ensure each piece of pasta is well-covered, allowing it to soak up the rich flavors.

Sprinkle the chopped parsley and basil (if using) over the pasta. These fresh herbs will brighten the dish and add a hint of freshness.

Transfer the pasta to serving plates, garnish with extra Parmesan or fresh herbs if desired, and enjoy immediately. This creamy, tangy, and savory pasta sauce is best served warm for maximum flavor.