Preheat oven to 350°F.
Beat together butter, corn syrup, brown sugar and egg yolk until smooth in a medium mixer bowl. Add flour, baking powder and salt; mix on low for 2 minutes until the flour mixture is combined. Pat dough in a greased 13 x 9-inch baking pan to create a crust. Bake for 5 to 6 minutes.
Combine all filling ingredients in a medium bowl until well incorporated. Spread the mixture over the warm crust, being careful not to crack the crust. Bake for an additional 20 to 24 minutes, until the coconut filling is golden brown.
Remove from the oven and place pan on a cooling rack. Sprinkle chocolate chips over the filling and let sit for 5 to 10 minutes to melt. Gently spread the melted chocolate chips over the top to cover the entire filling. Sprinkle with sliced almonds. Cool for 30 minutes. Place in refrigerator for 30 minutes until chocolate has set.