Bring a large pot of salted water to a boil. Add lasagna noodles and cook according to package instructions until al dente, about 8-10 minutes. Drain and drizzle with olive oil.

Melt 4 tablespoons of unsalted butter in a medium saucepan over medium heat. Whisk in ¼ cup of all-purpose flour and cook for about 1-2 minutes. Gradually pour in 2 cups of whole milk, whisking continuously for 5-7 minutes until thickened. Stir in salt, pepper, and desired amount of basil pesto.

In a mixing bowl, combine 15 ounces of ricotta cheese, 1 cup of grated Parmesan, 1 beaten egg, 1 teaspoon of dried basil, and ½ teaspoon of garlic powder. Mix until smooth.

Spread a layer of béchamel sauce in a greased 9x13 inch baking dish. Layer with noodles, half of the cheese mixture, and a third of the mozzarella. Top with basil pesto and repeat layers, finishing with béchamel and remaining mozzarella.

Preheat oven to 375°F (190°C). Cover lasagna with foil and bake for 50 minutes. Remove foil and bake for an additional 10-15 minutes until golden and bubbly.

Let the lasagna rest for about 15 minutes before slicing. Serve warm with a fresh salad or garlic bread.