Sauté the aromatics: Heat the olive oil or butter in a large skillet over medium heat. Add the onion and cook 3–4 minutes until softened.
Stir in the garlic and cook 30 seconds until fragrant.
Brown the beef: Add the ground beef. Season with salt, pepper, Italian seasoning, smoked paprika, and red pepper flakes if using. Cook, breaking it up, until no longer pink and lightly browned, about 5–7 minutes.
Manage the fat: If there’s excess grease, spoon off most of it, leaving about a tablespoon in the pan.
This keeps the sauce rich without being greasy.
Make it creamy: Reduce heat to medium-low. Add the cream cheese and stir until it begins to melt into the beef.
Add liquid: Pour in the heavy cream and beef broth. Stir until smooth and gently simmer 2–3 minutes to thicken slightly.
Wilt the spinach: Add the chopped spinach in batches, stirring until it wilts and blends into the sauce.
If using frozen spinach, make sure it’s well-drained so the sauce stays thick.
Cheesy finish: Stir in the mozzarella and Parmesan until melted and velvety. If the sauce gets too thick, add a splash more broth. If too thin, simmer 1–2 extra minutes.
Brighten and taste: Stir in lemon juice if using.
Taste and adjust salt and pepper. Remove from heat and garnish with parsley or chives.
Serve: Enjoy as-is, or spoon over sautéed zucchini, cauliflower rice, or shirataki noodles for a full meal.