Classic Creamed Spinach

2 boxes (10 oz each) frozen spinach
1/4 cup butter
1 small onion, chopped
2 cloves garlic, finely chopped
3 tablespoons Gold Medal™ all-purpose flour
2 1/2 cups whole milk
1 teaspoon salt
1/8 teaspoon pepper
Cook spinach as directed on box; drain well.

In 2-quart saucepan, melt butter over medium heat. Add onion; cook 4 to 5 minutes, stirring frequently. Add garlic; cook about 1 minute, stirring frequently, until onion is tender.

Stir in flour with whisk until mixture is smooth and bubbly, stirring constantly. Gradually stir in milk until mixture boils and thickens, stirring frequently. Stir in salt and pepper.

Stir in drained spinach; cook until thoroughly heated.