Cook spinach in a large pot with 1/4 inch water until steam has collapsed leaves, 8 to 10 minutes.
Drain, and squeeze out liquid.
2. In a medium skillet over medium heat, melt butter.
Whisk in flour, 1 teaspoon salt and some pepper.
Stir for 1 minute.
Whisk in milk and simmer until slightly thickened, about 1 minute.
Fold in chopped spinach.