Thaw spinach, squeeze and remove excess water, set aside.

In a medium sized skillet, melt the butter over medium heat. Add the minced garlic and cook for about 1 minute until fragrant. Be careful not to let the garlic brown.

Sprinkle the flour over the butter and garlic mixture. Stir continuously for about 2 minutes until the flour is well incorporated and begins to turn golden brown.

Slowly pour in the milk, whisking the entire time. The roux will begin to thicken, taking about 4-5 minutes.

Add the spinach. Season with salt, pepper, and nutmeg. Stir in the parmesan cheese. Simmer for five minutes.

Serve topped with additional parmesan if desired.