Wash the spinach and put it in a medium skillet while it's still wet.
Cook the spinach over medium heat, tossing, until it is wilted and tender. About 2-3 minutes.
Turn the stove off and allow it to sit and let the water evaporate. If there's a lot of water, you can drain it in a colander. It doesn't have to be completely dry.
Turn to medium-low and to the pan with the spinach, add the heavy cream, Parmesan cheese, garlic powder, onion flakes, salt, and pepper. (Start with just a pinch salt and pepper.)
Cook and stir until Parmesan is melted and the cream is reduced and thick. Serve immediately.