1Cook broccoli as directed on package, using 2-quart saucepan.
2In small bowl, combine 1/2 cup of the milk and flour; stir with wire whisk until well blended. Stir into broccoli in saucepan. Add remaining 2 1/2 cups milk, garlic salt, dry mustard and pepper; mix well. Cook and stir over medium heat until bubbly and thickened.
3Add cheese; cook 2 to 3 minutes or until melted and smooth, stirring occasionally. Add beer; cook until thoroughly heated, stirring constantly. Garnish with popcorn.