4Ataulfo mangos(ripe, about 2 pounds (900g) total, cut from the pit, diced, and scooped from the skin; yielding about 12 to 16 ounces (350 to 450g) diced fruit, see Note 1)
Preheat the oven to 350ºF. Lightly grease a 9-inch round cake pan and line it with a parchment round. Set aside.
Melt 4 tablespoons (57g) butter in a small pot over medium heat. Once melted, add ½ cup (100g) light brown sugar and ¼ teaspoon flaky sea salt. Stir to combine. Cook over medium heat for 3 minutes, stirring occasionally, until the sugar blends into the butter and the mixture darkens slightly in color.
Reduce the heat to low and add 2 tablespoons (30g) heavy cream and 1 teaspoon vanilla extract. Whisk until smooth and simmer for 1 minute. Turn off the heat and stir in the ½ cup (60g) toasted coconut flakes. Taste and add more flaky sea salt, if desired.
Pour the mixture into the prepared cake pan and smooth it into an even layer. Transfer to the refrigerator for 15 minutes.
Prepare the mango:
Place the diced mango in a bowl with 1 tablespoon (7g) cornstarch. Stir to coat. Set aside.
Make the batter:
Sift 1 cup (120g) all-purpose flour, 1 tablespoon (7g) powdered buttermilk, 1 teaspoon baking powder, and ¼ teaspoon kosher salt into a small bowl. Set aside.
Add 4 tablespoons (57g) of room temperature butter and ½ cup (100g) of granulated sugar to a large bowl. Use an electric hand mixer to cream them together. Add 1 egg and beat until smooth.
Add half the sifted dry ingredients and beat with the mixer until just combined. Add ½ cup (120g) milk and beat until just combined. Add the remaining dry ingredients along with 1 teaspoon vanilla extract. Beat until just combined. Don’t overmix!
Assemble the cake:
Remove the cake pan from the refrigerator. Spoon the diced mango on top. Gently press the mangos into the caramel to form a tightly packed layer. Pour the batter over the mangos and smooth it out with the back of the spatula.
Bake the upside-down cake:
Transfer the cake to the oven and bake for 45 to 47 minutes until a toothpick inserted into the center of the cake comes out clean.
Let the cake stand at room temperature for 60 minutes. The cake should still be warm to the touch.
Flip the cake:
Place a large plate over the cake pan and carefully invert the cake onto the plate.
To serve:
Slice the cake and serve with whipped cream or a scoop of vanilla ice cream on top, if desired. Enjoy!
Notes
Note 1: Ataulfo mangoes can be sold under a variety of names, including Champagne, honey, or yellow mango. The total yield will depend on your mangos and how much fruit you’re able to cut from the skin. I’ve made this recipe with a yield of 350g up to 450g of fruit, and it works well.Note 2: Cream of coconut is a sweetened product used in cocktails and desserts, not unsweetened coconut cream. If you don’t have it, just omit it and consider adding a ½ teaspoon of coconut extract instead.