Coconut Lemon Crumble Bars

TO MAKE THE LEMON FILLING combine the corn starch, salt, cake flour, sugar and water in a medium saucepan.
Cook over medium-low heat until the mixture thickens, stirring constantly. Remove from heat.
Pour about ½ cup of the thickened mixture over the beaten egg yolks and whisk together quickly. This tempers the egg yolks so that they do not scramble.
Pour this mixture back into the pot and whisk it in quickly. Return the pot to the heat and stir constantly for a few minutes until the mixture is thick and evenly smooth.
Whisk in the lemon juice and zest and remove from the heat.
Finally whisk in the butter and set aside to cool while you prepare the crumble mixture.
FOR THE CRUMBLE sift together the flour, sugar, baking powder, coconut and salt.
Using your hands or a pastry blender cut in the butter until the it is completely incorporated into the dry ingredients.
Press half of the crumb mixture into the bottom of a 9 x 13 inch well greased baking pan. Pour the lemon filling evenly over the bottom crumbs. Gently sprinkle the remaining crumbs over the lemon filling and press down gently.
Bake in a 350 degree F oven for 40 – 45 minutes or until light golden brown in color. Cool completely in the pan before cutting into squares and serving.