I have a treasured star fruit tree in my yard, which produces a crop of fruit several times a year. I end up with so much of this delicious tropical fruit; I’m forced to think of new ways to use it (even though my neighbors are very happy to accept my fruity gifts).
A few months ago, I wanted to make a star fruit upside-down cake, but the fruit on my tree wasn’t ripe enough. Instead, I made this delicious kumquat upside-down cake. The kumquat cake was better than I thought it would be. The tart kumquat skins, though a little chewy, were perfect with the sweet caramel-covered cake.
With my star fruit tree loaded with ripening fruit, I anxiously awaited the moment when I could make the upside-down cake again. Unfortunately, my waiting was prolonged, because one of my neighbors decided to take it upon herself (without asking) to pluck the ripest fruit from my tree as she walked her dog. She isn’t very tall, though, so the top branches were left untouched and I was able to find 2 tree-ripened fruit to make the long-awaited cake.
Visually, the star fruit upside-down cake is stunning, with drippy caramel and cake squeezed between the thick slices of fruit. Despite its fragile appearance, star fruit holds up well to cooking. It keeps its distinct star shape even in sauces. The flavor, however, is very subtle. Star fruit is very juicy, mildly sweet and a little tart, reminiscent of a kiwi.
I used a different recipe for the cake batter this time, and made a richer caramel topping. The cake is more substantial and buttery. It is very moist, with a touch of nutty flavor from the addition of ground almonds. The caramel topping could easily be made with a touch of rum to accent the tropical fruit even more.
So which cake is better, Kumquat or Star fruit upside-down cake?
I’ll just have to make them both again to have a real taste test.
You can make the entire cake using a large (10”) cast iron skillet. If you don’t have one, use a standard 9-inch cake pan. It’s up to you how much fruit to use. I recommend cramming as much as you can into the pan, because it will shrink together when it cooks.
Melt the butter and brown sugar (and rum if using) over medium heat in your skillet or a heavy saucepan, until the sugar is melted and bubbly, about 5-10 minutes. If you added rum, cook 5 minutes longer on low heat. Try not to stir it around too much, because it isn’t necessary. Remove from the heat. If you are using a cake pan instead of a cast iron skillet, pour the caramel into the bottom of the cake pan.
When the caramel is cool, arrange the fruit from the outside-in. Squeeze as much fruit in the bottom as you can. Set aside.
Preheat the oven to 325° F/ 170° C
Combine the flour, ground almonds, baking powder and salt in a large mixing bowl. In a separate bowl, beat together the butter and sugar with an electric mixer until light and fluffy. Add the eggs to the butter mixture one at a time, beating until combined. Add the vanilla extract. Alternate adding the dry ingredients and the yogurt everything is blended.
Pour the cake batter over the fruit layer and spread evenly (it will be thick). Bake 50 minutes to 1 hour, until a cake tester inserted into the middle comes out clean. Cool for 15 minutes.
Carefully turn the cake out onto a large platter, taking care as there will be hot caramel that may drip through the sides of the pan. Best served warm or room temperature.