1-Thaw frozen spinach at room temperature or in the microwave, then squeeze out all excess water thoroughly to avoid a watery dish.

2-Bring a large pot of water to a boil and cook 2 cups uncooked macaroni for 7-10 minutes until tender, then drain well.

3-In a small saucepot over medium heat, melt 2 tablespoons butter and stir in 2 tablespoons all-purpose flour to form a smooth paste, cooking for about 1 minute to lightly toast the flour.

4-Gradually whisk in 2 cups whole milk, bring to a simmer while stirring continuously, and allow the sauce to thicken for a creamy base.

5-Remove from heat and whisk in 1/2 cup grated Parmesan cheese and 1/4 cup basil pesto until smooth, then season with 1/2 teaspoon salt and freshly cracked black pepper to taste.

6-Return the drained macaroni to the large pot with heat off, add the squeezed spinach, and pour the prepared sauce over the macaroni and spinach.

7-Mix gently until everything is evenly coated, then serve immediately for the best texture and flavor.