Pre-heat oven 350
In a medium mixing bowl, beat the ½ cup butter, sugar, and salt with an electric mixer on medium to high speed till combined. Using a wooden spoon, stir in the flour. Press into the bottom of an ungreased 13X9X2 inch baking pan. Bake in a 350 degree oven about 15 minutes or till the edges are lightly browned.
Meanwhile, in a heavy medium saucepan, heat the sweetened condesned milk and 2 tablespoons butter over medium heat till bubbly, stirring constantly. Cook and stir for 5 minutes more (mixture will thicken and become smooth). Stir in the 2 teaspoons vanilla. Spread over baked layer (best if the baked layer has had a few minutes to cool). Bake for 12 to 15 minutes or till golden.
For fudge icing, in a small saucepan melt chocolate and 2 tablespoons butter over low heat, stirring occasionally. Remove from heat. Stir in the powdered sugar and the 1 teaspoon vanilla. Stir in enough HOT water (1 to 2 tablespoons) to make an icing that is easy to pour. Spread the icing evenly over the warm cookie. Immediately cut into bars. Cool on a wire rack. Makes 36 (or 8 Mike and Ange size bars).