black bottom coconut-graham bars
base recipe adapted from Martha Stewart

chocolate base:
1/2 cup (1 stick) unsalted butter, plus more for pan
1/2 cup sugar
1/4 teaspoon salt
1 large egg
1/4 cup unsweetened cocoa powder
1/4 cup all-purpose flour (spooned and leveled)

graham center: (I added this in, optional but wonderful)
3/4 cup crushed graham crackers, (I like rough chop, not powder, to keep it crunchy)
4 ounces melted butter

coconut topping:
2 large eggs
3/4 cup sugar (I used ½ cup)
1/2 ts vanilla extract (I used almond extract)
1 cup all-purpose flour (spooned and leveled)
1 package sweetened shredded coconut (7 ounces), 1/2 cup reserved for sprinkling

Cook notes:

The original recipe does not call for a graham center. I wanted to add this in for a nice crunch effect. Up to you if you want to add it in—it does lend a nice flavor and texture.
Also, I ran into a problem with Martha’s original recipe. In Martha’s recipe, it says to pre-bake the chocolate base for 10-15 minutes; I only prebaked it for 7 minutes. 
 On the first batch, I did the 10-15 minutes, it was way too long/much and it ended up being overdone when I had to bake it again. 
So I highly suggest only prebaking for 5-7 minutes or not even prebaking it at all. The chocolate base is VERY THIN. 
Maybe if you double the base ingredients, then prebaking would come out fine. 
Also the original recipe says it makes 24 bars? From an 8-9 inch pan? I only got about 12.

For chocolate base:

Preheat oven to 375 degrees. Line a 9-inch square baking pan with aluminum foil, leaving a slight overhang; butter bottom and sides of foil (not overhang).
Place butter in a large microwave-safe bowl; melt in microwave. Add sugar and salt; whisk to combine. Whisk in egg, then cocoa and flour until smooth. Spread batter in prepared pan. 
 Bake just until sides begin to pull away from edges of pan, 10 to 15 minutes (I only prebaked for 5-7 minutes). Let cool slightly while preparing coconut topping. Keep oven on for next sets of toppings.

For graham center:
Melt 4-5 ounces of butter, let cool a bit. Then mix with the ½ cup of crushed graham. Sprinkle this mixture over the chocolate base. Next move onto the coconut topping.

For coconut topping: 
In a medium bowl, whisk eggs with sugar and vanilla. Gently mix in flour and coconut (except 1/2 cup reserved for sprinkling).
Drop mounds of mixture over chocolate base; spread and pat in gently and evenly with moistened fingers. Sprinkle with reserved 1/2 cup coconut.
Bake until golden and a toothpick inserted in center comes out with moist crumbs attached, 25 to 30 minutes (mine was done at 22-23 minute mark). 
Cool completely in pan. Lift cake from pan, peel off foil, and cut into 24 bars (mine made 12 bars). Store in an airtight container 3 to 4 days.