Preheat the oven to 350°F.

In a deep skillet, melt 4 tablespoons of butter. Add flour, salt, and pepper to the butter and saute 2-3 minutes until the flour begins to brown.

While whisking constantly, gradually add the milk. The mixture will whisk into a thick paste and eventually a sauce as the milk is added. Once the milk is fully incorporated, continue cooking until mixture comes to a simmer and thickens.

Stir in 1 cup of mozzarella cheese and 1 cup of parmesan cheese, adding a handful at a time and stirring each addition until melted and smooth.

Whisk in pesto sauce and adjust to your preferred taste.

Meanwhile, in a large pot of salted water, cook the tortellini for 2 minutes less time than the package instructions (mine cooked for 5 minutes). You want the tortellini al dente as it will continue cooking in the oven.

In a large casserole dish (3 Qt.), layer half of the cooked and drained tortellini, Spoon half of the prepared pesto sauce over the tortellini. Sprinkle with 1 cup of halved cherry tomatoes and half of the remaining cheeses.

Add a second layer of tortellini, sauce, tomatoes and cheese.

Bake for 20-30 minutes, or until the cheese on top of the dish is melted, bubbly, and beginning to brown.

Garnish with fresh cracked pepper and fresh basil, if desired.