Cook the Pasta:

Bring a large pot of salted water to a boil.

Cook the pasta according to package directions until al dente.

Drain and set aside.

Make the Sauce:

In a large saucepan or deep skillet, melt the butter over medium heat.

Whisk in the flour and cook for 1–2 minutes to form a roux.

Slowly whisk in the milk until smooth and thickened (3–5 minutes).

Stir in marinara sauce, Italian seasoning, garlic powder, salt, and pepper.

Reduce heat to low and stir in mozzarella, cheddar, and Parmesan cheese until melted and smooth.

Combine and Add Toppings:

Add the cooked pasta to the sauce and stir to coat completely.

Stir in half of the pepperoni and olives (if using).

Transfer the mixture to a greased 9x13-inch baking dish (optional for baking) or keep it in the pan.

Top and Bake (Optional):

Sprinkle the remaining cheese and pepperoni on top.

Bake at 375°F (190°C) for 10–15 minutes, or until bubbly and lightly golden on top.

Skip this step if serving straight from the stovetop.

Serve:

Garnish with fresh parsley or basil and serve hot!