To 350°F. Line a 13x9-inch baking pan with foil, extending foil over edges. Coat foil with cooking spray.
, in a small bowl, stir together flour, cornstarch, baking powder, and salt. Set aside.
With a mixer on medium for 30 seconds in a large bowl.
And beat on medium to high until light and fluffy. Beat in egg yolk and vanilla.
Mixture (mixture will be crumbly).
Into the bottom of the prepared pan, and bake 10 to 12 minutes or until edges are light brown.
, place the coconut in a large bowl, pour in the caramel sauce and stir to combine.
From the oven and immediately sprinkle 1 ½ cups of the chocolate chips over the hot crust; let stand 5 minutes. Then spread the chocolate over the crust.
Coconut mixture over the chocolate layer. Bake 10 minutes more. Cool in pan on a wire rack.
Remaining chocolate chips in a small bowl for 20 seconds. Then stir and microwave for another 10-15 seconds until melted and smooth. Drizzle over coconut mixture.
And put in the refrigerator for at least 1 hour until it sets. Pulling on the foil edges, lift out the uncut block, and cut into bars.
