Melt the butter in a large skillet over medium-high heat until it starts to bubble slightly. Season the shrimp with salt, pepper, and paprika on both sides before adding them to the pan. Cook for about thirty seconds per side, just until they turn pink, then remove them and set them aside on a plate.
Lower the heat slightly and add the minced garlic and crushed red pepper to the same skillet. Stir constantly for about fifteen seconds, just until the garlic turns fragrant, since burnt garlic will make the whole sauce taste bitter. This step only takes a few seconds, so do not walk away from the stove.
Add the chopped spinach to the skillet and season lightly with salt and pepper. Stir it for one to two minutes until it wilts down completely and shrinks in volume. This is a good moment to scrape up any browned bits from the bottom of the pan for extra flavor.
Pour in the heavy cream and sprinkle in the grated parmesan cheese, stirring until the cheese melts smoothly into the cream. Let the sauce simmer gently for five to seven minutes, stirring occasionally, until it thickens enough to coat the back of a spoon. Taste it here and adjust the salt and pepper as needed.
Return the cooked shrimp to the skillet along with any juices left on the plate. Cover the pan and let everything cook together for another thirty seconds to a minute, just until the shrimp are heated through. Avoid overcooking at this stage, since shrimp turn tough very quickly.
Sprinkle fresh chopped parsley over the top right before serving for a bright finishing touch. Serve the dish immediately while the sauce is still warm and glossy. This is the moment where the whole kitchen smells incredible, so do not let it sit too long before digging in.