line a 9 x 13 inch baking pan with parchment and lightly grease
whisk melted butter brown sugar and granulated sugar until smooth
whisk in eggs and vanilla until fully combined.
Bake and Cool
stir flour baking powder and salt into wet mixture just until no dry streaks remain
fold in shredded coconut and chocolate chips if using
spread batter evenly in prepared pan and press into corners
bake until edges are light golden and center is set and a toothpick comes out with a few moist crumbs about 20 to 25 minutes
cool completely in pan then lift out and slice into bars.
Notes
1. For extra chewiness slightly underbake and cool fully before cutting; Use unsweetened coconut for less sweetness or toast coconut for deeper flavor; Add 1/2 cup chopped nuts or swap chocolate chips for white chocolate chips