1. Preheat oven to 425°F. In large bowl, combine flour, baking powder and salt. Cut in shortening and butter until mixture resembles coarse crumbs. Combine beer and 1 tablespoon mustard; stir into crumb mixture just until blended. Turn onto floured surface; knead gently 8 times.
2. Pat dough to 1/2-inch thickness. Cut out biscuits with 2-inch round biscuit cutter. Reroll scraps and cut out additional biscuits. Place 1-inch apart on a greased baking sheet. Combine remaining mustard with milk and brush over tops. Bake 13 to 15 minutes or until lightly browned.