In a pot, bring the water and salt to a boil. Add the spinach and cook for about 5 minutes.
Pour the spinach into a sieve to drain, reserving the cooking liquid.
Finely chop the cooked spinach. Set aside.
Melt the butter in a saucepan over low heat and stir in the flour. Sauté for about 2 to 3 minutes, stirring continually.
Add the milk and ½ cup of the reserved cooking liquid. Stir with a whisk over low heat until smooth.
Add the garlic and simmer for about 5 minutes.
Add the chopped spinach. Season with salt, pepper, and nutmeg. Heat thoroughly before serving.
