Preheat oven to 350 degrees F.
Grease a 13 by 9 by 2-inch pan and set aside. In a mixing bowl, stir together flour, sugar, and salt. Add butter, eggs, orange extract, and orange zest and beat with a handheld electric mixer until well blended. Pour batter into prepared pan and bake for 30 minutes, or until light golden brown and set. Remove from oven and pierce top of entire cake with a fork.
Glaze: Combine all ingredients in a bowl, stirring until smooth. Pour glaze over cake. Cool cake and cut into squares.