Trim and wash 1 pound of fresh spinach thoroughly under cold water. Steam the spinach for about 3-4 minutes until it wilts. Transfer to a colander, drain, and squeeze out excess moisture.

In a Dutch oven, melt 2 tablespoons of butter over medium-high heat. Add 1 finely chopped onion and sauté for 5-7 minutes until tender and translucent.

Sprinkle in 2 tablespoons of flour, ½ teaspoon of salt, and ¼ teaspoon of white pepper, stirring for about 1 minute. Gradually whisk in 1 cup of whole milk and ½ cup of heavy whipping cream, bringing to a low boil and stirring until thick (1-2 minutes).

Add ½ cup of grated Parmesan cheese, stirring until melted. Fold in the wilted spinach and heat through for another 2-3 minutes on low heat.

Transfer to a serving dish, garnish with extra Parmesan and a sprinkle of white pepper, and serve immediately.