FOR CHOCOLATE BASE1/2 cup (1 stick) unsalted butter, plus more for pan1/2 cup sugar1/4 teaspoon salt1 large egg1/4 cup unsweetened cocoa powder1/4 cup all-purpose flour (spooned and leveled)
FOR COCONUT TOPPING2 large eggs3/4 cup sugar1/2 teaspoon vanilla extract1 cup all-purpose flour (spooned and leveled)1 package sweetened shredded coconut (7 ounces), 1/2 cup reserved for sprinkling
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).
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.
just until sides begin to pull away from edges of pan, 10 to 15 minutes
(do not overbake). Let cool slightly while preparing coconut topping.
Keep oven on for topping.
coconut topping: In a medium bowl, whisk eggs with sugar and vanilla.
Gently mix in flour and coconut (except 1/2 cup reserved for
mounds of mixture over chocolate base; spread and pat in gently and
evenly with moistened fingers. Sprinkle with reserved 1/2 cup coconut.
until golden and a toothpick inserted in center comes out with moist
crumbs attached, 25 to 30 minutes. Cool completely in pan. Lift cake
from pan, peel off foil, and cut into 24 bars. Store in an airtight
container 3 to 4 days.