LIne a 9x9-inch pan with parchment paper or wax paper. Combine graham crumbs, cocoa, powdered sugar, and coconut. In a separate dish, melt the butter and chocolate chips together in the microwave in 15-second increments, stirring between each increment. Add to the dry ingredients and mix until combined. Press firmly into the prepared pan and refrigerate while making the custard layer.

Beat together softened butter, custard powder, milk, and powdered sugar using a handheld mixer starting on low and increasing to high as the mixture starts to come together. Beat on high speed for 2 minutes or until fluffy. Using an offset spatula, gently spread the custard onto the chilled crust, being careful not to pull up the crust layer. Refrigerate for 1 hour.

Gently melt the chocolate chips and butter together in the microwave in 15-second increments or on the stovetop. Once the other layers have chilled, gently spread the chocolate mixture on top of the custard layer. Refrigerate for at least 1 hour. Slice into 32 squares to serve. Enjoy!