Preheat oven to 375 degrees. Butter a 9” x 13” casserole dish and set aside.

Bring a large pot of salted water to a rapid boil over high heat then cook macaroni for about 3 minutes less than directed on the package. Drain thoroughly, transfer to a large bowl and set aside.

Place a large saucepan over medium-high heat and melt butter. Add garlic and cook for about 30 seconds. Add flour then whisk until combined. Allow mixture to cook for about 30 seconds before slowly whisking in warm milk. Whisk until no lumps remain then bring to a boil, stirring constantly.

Reduce heat to medium-low then stir in salt and pepper. Simmer for 6–7 minutes, allowing sauce to thicken slightly. Remove sauce from heat then set aside.

Add tomatoes, basil and pesto to the bowl of cooked macaroni then stir to distribute. Add about 1 cup of shredded mozzarella, season with salt and red pepper flakes then stir to combine. Add remaining mozzarella then stir until mostly melted.

Combine sauce with pasta then stir to coat evenly.

Pour mixture into prepared baking dish, cover with foil then bake for 30 minutes. Uncover and bake 15 minutes longer. Remove from oven then let sit for 5 minutes before sprinkling with additional basil. Enjoy!