Preheat the oven to 350 degrees. Spray either a 3 quart casserole dish or 9×13 baking dish with nonstick spray and set aside.

Combine the shredded cheddar and Gruyere cheeses together in a large bowl and set aside.

Cook the pasta to just before being done, drain and then drizzle with olive oil. Set aside to cool while you make the cheese sauce.

In a deep saucepan, melt the butter on medium heat. Add the flour and whisk together for about 1 minute. Slowly pour in the heavy cream then the whole milk, whisking at the same time to combine. Continue whisking until the mixture just starts to bubble slightly. Add in salt and pepper, continue whisking for another 2 minutes.

Add 2 handfuls of the shredded cheese mixture, stirring afterwards to combine and melt together. Add another 2 handfuls (be sure to leave a handful to top the baking dish). Stir again to combine and melt.

Once the sauce is smooth and melted, add in the cooked pasta and stir together to coat the pasta.

Add half the cheesy pasta mix to the casserole dish and spread out. Sprinkle with the remaining shredded cheese. Top with the remaining pasta and cheese mixture.

In a separate medium bowl, combine the 4 Tablespoons melted butter, Panko, shredded Parmesan and Paprika together. Sprinkle on top of the pasta.

Bake at 350 degrees for 30 minutes until the sides start to get bubbly then serve!