Preheat the oven to 350°F. Boil pasta in salted water and cook for the minimum package time. Drain and place into a baking dish.
In a saucepan over medium heat, warm the heavy cream. Add 2 cups of cheddar, the gruyere, smoked paprika, and salt. Stir until melted and smooth, then bring to a gentle simmer.
Pour the cheese sauce over the pasta and stir to coat every noodle.
Sprinkle the remaining 2 cups of cheddar on top. Bake uncovered for 20–25 minutes, or until the top is golden and bubbling. Serve hot and enjoy.