1. Preheat your oven to 350°F (175°C). Grease a 9×13 inch baking dish and set aside.
2. Cook the pasta in a large pot of salted boiling water until al dente, about 8 minutes. Drain and set aside.
3. In the same pot, melt the butter over medium heat. Whisk in the flour and cook for about 1 minute until golden and bubbly.
4. Gradually whisk in the milk and heavy cream, ensuring there are no lumps. Cook until the sauce has thickened, about 5 minutes.
5. Remove the pot from heat and stir in the cheddar, Gruyère, and half of the Parmesan cheese until melted and smooth. Season with ground mustard, paprika, salt, and pepper.
6. Add the cooked pasta to the cheese sauce, stirring to combine. Transfer the mixture to the prepared baking dish.
7. In a small bowl, mix the breadcrumbs with the melted butter and remaining Parmesan cheese. Sprinkle over the pasta.
8. Bake for 25-30 minutes, or until the top is golden brown and the sauce is bubbly.
9. Let the mac and cheese sit for 5 minutes before serving. Garnish with fresh parsley.

Notes

• Feel free to experiment with different cheeses to find your perfect blend.
• For a gluten-free version, use gluten-free pasta and flour.
• Add cooked bacon, lobster, or roasted vegetables for extra flavor and texture.