In a large skillet, heat the olive oil over medium heat. Add the minced garlic and sauté for about 1 minute until fragrant, being careful not to burn it.
Add the shrimp to the skillet and season with salt, pepper, and red pepper flakes if using. Cook for about 2-3 minutes on each side until the shrimp are pink and opaque. Remove the shrimp from the skillet and set aside.
In the same skillet, pour in the heavy cream and bring to a gentle simmer. Stir in the chopped spinach and cook until wilted, about 2 minutes.
Add the Parmesan cheese to the cream mixture, stirring until melted and combined. Return the cooked shrimp to the skillet and mix well to coat in the sauce. Cook for an additional 2 minutes to heat through.
Serve the creamy garlic shrimp over cooked pasta or rice, garnished with fresh parsley.