Paired together with a chocolate drizzle, the texture of this cake turns out a decadent bite not unlike that of a candy bar. Martha made this recipe in episode 506 of Martha Bakes
Cake: Preheat oven to 350 degrees. Butter and flour a 10-inch springform pan. Whisk together flour, baking powder, baking soda, and salt. In another bowl, stir together cream of coconut and vanilla.
Beat butter and coconut oil on medium-high until smooth. Slowly add sugar; beat until pale and fluffy, 3 to 5 minutes. Reduce speed to medium; add eggs, one at a time, beating well after each and scraping down sides of bowl as needed. With mixer on low, add flour mixture in 3 batches, alternating with 2 batches of cream-of-coconut mixture. Beat until just combined.
Topping: In a large bowl, whisk together egg whites and salt until thick and frothy, about 1 minute. Stir in milk and vanilla. Fold in coconut.
Spread cake batter in pan. Pour topping over batter; carefully spread in an even layer. Bake on a rimmed baking sheet until a toothpick comes out with just a few moist crumbs, about 1 hour (tent with foil if browning too quickly).
Chocolate Sauce: In a small saucepan, bring heavy cream and sugar almost to a boil, stirring, until sugar is dissolved. Pour over chocolate and butter in a heatproof bowl. Stir until smooth, then stir in vanilla.
Let cake cool completely; remove from pan. Cut into wedges, drizzle with chocolate sauce, and serve with extra sauce on the side.