Beat shortening,butter and brown sugar at medium speed with an electric mixer 2 minutes or until creamy. Add eggs, one at a time, beating well after each addtion.
Combine flour,salt,and baking powder; add alternately with milk, beginning and ending with flour mixture. Stir in flavoring. Pour batter into a greased and floured 12-cup bundt pan.
Bake at 300 for 1 hour and 15 minutes or until a long wooden pick inserted into the center comes out clean. Cool in pan on wire rack 15 minutes. Remove from pan, and cool completely on a wire rack. Pour warm glaze over cake. Let cake stand 30 minutes or until glaze is firm.
BROWN SUGAR GLAZE:
Melt butter in a medium saucepan over medium heat. Whisk in brown sugar, and cook 1 minute.
Add milk, powdered sugar, and vanilla; whisk until creamy. Remove from heat, and pour immediately over cooled cake.