Preheat oven to 375°F (190°C). Grease a 9x13-inch baking dish.
Cook pasta according to package instructions until al dente. Drain and set aside.
In a large skillet, heat olive oil over medium heat. Add garlic and sauté for 1 minute until fragrant.
Add artichoke hearts and cook for 3-4 minutes, stirring occasionally.
Stir in spinach and cook until wilted, about 2-3 minutes.
Reduce heat to low. Stir in heavy cream, milk, Parmesan, 1 cup mozzarella, salt, pepper, and red pepper flakes. Simmer for 3-4 minutes until slightly thickened.
Add cooked pasta to the sauce and stir until well coated.
Transfer mixture to the prepared baking dish. Top with remaining 0.5 cup mozzarella and breadcrumbs.
Bake for 25-30 minutes, or until bubbly and golden on top.
Let cool for 5 minutes. Garnish with parsley if desired, then serve.
Notes
For a lighter version, substitute half-and-half for heavy cream and use part-skim mozzarella. Leftovers can be refrigerated for up to 3 days and reheated in the oven.