Preheat oven to 325 degrees.
Combine flour, baking soda, and salt in a medium bowl and whisk together. Set aside.
In a medium saucepan, combine sugar, shortening, and water. Over medium heat, bring to a boil while stirring constantly. Remove from heat. Add chocolate morsels and vanilla and stir until smooth. Add eggs one at a time, stirring well after each addition. Add dry ingredients and walnuts and stir until thoroughly mixed.
Spoon batter into a greased 9-inch square pan. Bake for 25 minutes, or until a wooden pick inserted in the center comes out clean.
Evenly drizzle bourbon over brownies. Cool brownies completely.
For white icing, combine butter and vanilla in a large mixing bowl. Using an electric mixer, beat at medium speed until creamy. Gradually add in powdered sugar and beat until smooth.
Spread brownies with White Icing.
For Chocolate Glaze, combine morsels and shortening in a heavy bottomed small saucepan (or a double boiler). Heat over very low heat, stirring constantly until chocolate is melted.
Pour warm Chocolate Glaze over top of white icing. Let set and cut into squares.