Combine first 6 ingredients in a medium bowl; stir well, and set aside. Beat brown sugar and butter in a large bowl at medium speed of a mixer until light and fluffy. Add molasses and egg, beating well. Add flour mixture to butter mixture alternately with very hot water, beginning and ending with flour mixture; beat well after each addition.
Place 18 paper muffin cup liners in muffin cups; divide batter evenly among cup liners. Bake at 350° for 20 minutes or until a wooden pick inserted in center of 1 cupcake comes out clean. Let cool in pans 10 minutes on a wire rack; remove cupcakes from pans, and place on wire rack. Poke several holes in the top of each warm cupcake with a wooden pick; brush lemonade concentrate evenly over cupcakes. Let cool completely.
Spoon about 1 teaspoon Lemonade Glaze on each cupcake, and spread gently. Let stand until glaze sets.