Boil large pot of water. Add thawed spinach using hands. Blanch 1 minute. Drain in colander. Squeeze dry hard with hands over sink-get every drop. Chop coarse with knife. Set aside.
Melt 4 tbsp butter in large skillet over medium heat using wooden spoon. Add minced garlic. Stir 30 seconds till fragrant. Whisk in ¼ cup flour. Cook whisk 2 minutes till bubbly blond-no brown.
Pour half-and-half slow while whisk constant 3 minutes till thickens coats spoon. Drop cream cheese cubes. Stir wooden spoon 2 minutes melts smooth. Add Parmesan, salt, pepper, nutmeg. Stir 1 minute blends.
Fold chopped spinach into sauce using wooden spoon. Simmer low 5 minutes stir often till creamy thick clings leaves. Taste. Adjust salt. Serve hot bubbling.
