Step 1

Start by preparing your white sauce. Melt the butter over medium heat in a medium-sized saucepan. Remove the pan from the heat and add your flour. Using a whisk, combine the melted butter and flour until it forms a roux (a thick paste of flour and butter).

Step 2

Then, still off the heat, add 2 tablespoons of milk at a time while whisking well to incorporate the milk. If you add the milk too fast, your white sauce will have lumps. Rather take your time to create a beautiful smooth sauce.

Step 3

Continue adding the milk and whisking until all the milk has been incorporated. Add the liquid back onto low to medium heat and whisk continuously, scraping the sides and corners of the pan. The sauce is ready when it is completely smooth and thick. Season it with salt to your liking. Place saran wrap on the surface of the sauce and set aside until ready to use.

Step 4

To make the spinach mixture, melt the 2 tablespoons butter in a large pan on medium heat. Add the onions and sauté for 3-4 minutes. Add the spinach and water to the onions and reduce the heat.

Step 5

Place a lid on the pan and cook the spinach until it is completely soft, about 5 minutes. Stir every minute to prevent the spinach from sticking. The water should be completely evaporated before adding the sauce.

Step 6

Lastly, add the white sauce and sour cream. Fold them into the spinach until completely incorporated.