Cook the Pasta: Bring a large pot of salted water to a boil and cook 1 pound of ziti according to package directions. Drain and set aside.
Cook the Bacon: In a skillet or in the oven, cook 6 slices of bacon until crisp. Once cooked, transfer to a paper towel-lined plate to drain, then chop or crumble into bite-sized pieces. Set aside.
Sauté the Mushrooms and Garlic: In a large non-stick skillet, heat 1 tablespoon olive oil over medium heat. Add 8–10 ounces of sliced mushrooms and cook until tender and browned, about 6–8 minutes. Stir in 3 minced garlic cloves and cook for 1 more minute. Remove the mushrooms and garlic from the skillet and set aside.
Make the Cream Sauce: In the same skillet, melt 3 tablespoons butter over medium heat. Add the remaining 2 tablespoons olive oil. Once hot, pour in 2 cups heavy cream and whisk to combine. Bring to a gentle simmer, stirring frequently to prevent burning.
Add Parmesan and Thicken the Sauce: Stir in 1 cup grated Parmesan cheese and let the sauce simmer for 8–10 minutes, stirring often, until it starts to thicken.
Finish the Sauce: Reduce the heat to low. Stir in 1 cup shredded Mozzarella cheese, 1 teaspoon smoked paprika, and ½ teaspoon black pepper. Add the chopped bacon, 1–2 cups fresh spinach, and the reserved mushrooms and garlic. Stir until the spinach wilts and everything is heated through.
Combine with Pasta: Add the cooked ziti to the sauce and toss to coat evenly. Taste and adjust with salt and additional black pepper, if needed.
Serve: Serve immediately, garnished with extra grated Parmesan cheese if desired.