Drain cherries, reserving juice; set cherries aside. In a small saucepan, combine the sugar, cornstarch, water and reserved juice until smooth. Stir in cherries; heat through. Transfer to a greased 8-in. square baking dish.
In a large bowl, combine the flour, 3 tablespoons brown sugar, baking powder and salt. Cut in shortening until crumbly. Combine egg and milk; stir into crumb mixture just until blended.
Turn onto a lightly floured surface; knead 3-4 times. Roll into a 14×10-in. rectangle. Spread with butter. Combine cinnamon and remaining brown sugar; sprinkle over top.
Roll up, jelly-roll style, starting with a short side. Cut into eight slices; place cut side down over cherry filling.
Bake at 400° for 25-30 minutes or until golden brown. Cool for 10 minutes. Combine glaze ingredients; drizzle over cobbler.