Pre-heat oven to 350 degrees. Cream butter and powdered sugar together. Add salt and flour and mix well. Pat into greased 9 x 13 baking pan. Bake at 350 degrees for 15-20 minutes until golden brown. Remove from oven.
Mix all filling ingredients while crust bakes. Pour filling over hot crust. Bake at 350 for and additional 20-25 minutes. Remove from oven and sprinkle with powdered sugar. Cool before cutting into bars.
Source: Jerie Jacobs