1 lb. boneless skinless chicken breasts, cut into pieces
2 tsp. dried oregano
Freshly ground black pepper
2 tbsp. balsamic vinegar
3 cloves garlic, minced, divided
3 tbsp. butter
3 tbsp. all-purpose flour
2 1/2 c. milk
5 c. shredded mozzarella, divided
3/4 c. freshly grated Parmesan
1 16-oz. container ricotta
1 large egg
4 roma tomatoes, thinly sliced
1/2 c. thinly sliced basil leaves, plus more for garnish
Balsamic glaze, for drizzling
Preheat oven to 375º. In a large pot of salted boiling water, cook lasagna noodles until very al dente. Drain.
Meanwhile, in a large skillet over medium heat, heat oil. Season chicken with oregano, salt, and pepper. Cook until golden and cooked through, 8 minutes. Add balsamic vinegar and half the garlic to pan and stir until combined. Transfer to a plate.
Make sauce: Bring skillet back to medium heat and melt in butter. Add remaining garlic and cook until fragrant, 1 minute. Add flour and cook until golden, 1 minute more. Add milk and simmer until thick and creamy, 3 minutes, then add Parmesan and 1 cup mozzarella. Season with salt and pepper.
In a small bowl, stir together ricotta and egg and season with salt and pepper.
In a large baking dish, spread a thin layer of sauce. Add a layer of lasagna noodles, slightly overlapping, and top with about a third of ricotta mixture, a third of tomatoes, a third of the basil, a third of the cooked chicken, another layer of sauce, and a third of mozzarella. Repeat for a total of three layers, ending with mozzarella.
Bake until bubbly and golden, 25 to 30 minutes. Garnish with basil and drizzle with balsamic glaze before serving.