Cream together butter and sugar into stand mixer. Add flour and lemon zest and pulse until crumbly (cookie dough like texture).
Pierce with fork and bake at 350° for 20 minutes.
TOP LAYER
Mix together sugar and eggs until light in color about 3 minutes. Add lemon juice, ClearJel, baking powder, lemon zest, salt, and lemon extract. Mix until just incorporated.
Pour lemon filling onto baked crust.Bake at 350° for 25 minutes.Allow to cool for at least 1-2 hours.
After the bars have cooled, sprinkle powdered sugar all over the top and cut into bars into squares.Store in container.