1-Preheat oven to 325°F (163°C). Grease a 3-quart (9 x 13 in) baking dish.

2-Bring a large pot of salted water to a boil. Add pasta and cook until about 1 minute less than package instructions (slightly under al dente). Drain and toss with a little olive oil to prevent sticking.

3-Shred the cheeses and divide the total shredded cheese into three portions: about 3 cups (≈340 g) for the sauce, 1 1/2 cups (≈170 g) for the middle layer, and 1 1/2 cups (≈170 g) for the topping.

4-In a large saucepan over medium heat, melt the butter. Whisk in the flour and cook, whisking, for about 1 minute to form a roux.

5-Gradually whisk in about 2 cups (480 mL) of the half-and-half until smooth, then add the remaining half-and-half (120 mL) and the whole milk (360 mL) slowly, whisking constantly.

6-Continue cooking over medium heat, whisking, until the sauce thickens to a consistency similar to thinned condensed soup.

7-Remove the sauce from heat. Stir in the salt, black pepper, smoked paprika and about 1 1/2 cups (≈170 g) of the shredded cheese until melted. Add the remaining 1 1/2 cups (≈170 g) of the cheese reserved for the sauce and stir until smooth.

8-In a large bowl, combine the drained pasta with the cheese sauce so the pasta is evenly coated.

9-Place half of the pasta-and-sauce mixture into the prepared baking dish. Sprinkle with the 1 1/2 cups (≈170 g) of shredded cheese reserved for the middle layer. Add the remaining pasta mixture on top and finish by sprinkling the final 1 1/2 cups (≈170 g) of shredded cheese over the top.

10-Bake for about 15 minutes, until bubbly and lightly golden on top. If you prefer a crisper top, broil for 1 2 minutes at the end while watching closely.