Preheat oven to 425°F.
First Layer: Grease 10-inch Bundt pan with butter. Pour dulce de leche into pan and tilt to evenly coat bottom.
Flan Layer: In medium bowl, whisk together eggs, condensed milk, evaporated milk and vanilla until smooth. Pour into Bundt pan. Transfer Bundt pan to large roasting tray. Fill roasting tray with warm water, ensuring water reaches halfway up Bundt pan.
Bake for 30 minutes or until flan is almost set (firm enough to hold cake batter on top). Remove from oven and reduce oven to 350°F.
Chocolate Cake Layer: In large bowl, using handheld electric mixer, beat together butter and sugar until smooth and fluffy. Beat in egg.
In another medium bowl, whisk together flour, cocoa powder, baking powder and baking soda. Stir flour mixture into sugar mixture until combined. Stir in coconut milk and cream of coconut until smooth and incorporated. Pour mixture on top of flan layer and cover with foil.
Return to water bath and bake for 1 hour 15 minutes or until skewer comes out clean when inserted into center of cake. Let cool for 1 hour or until cake reaches room temperature.
Assembly: Place large plate over top of Bundt pan and invert to release cake from pan. Drizzle with dulce de leche and top with coconut.
Tip: Serve with fresh fruit, such as mango, pineapple and strawberries, if desired.