Kumquat Upside-Down Cake
This cake, which starts in a cast iron skillet stovetop then finishes in the oven, is sweet and tart and totally delicious, a perfectly citrusy cake to make all winter long. Fortunately, kumquats keep well in the fridge and do make a fabulous upside-down cake.
1½ lbs kumquats, halved
1 stick (4 oz) unsalted butter (113 g)
¾ cup Erythritol Gold
3 Tbsp. pure honey
½ tsp. pure vanilla extract
½ tsp. sea salt
1 ⅓ cup all-purpose flour, unbleached
1½ tsp. baking powder
¾ tsp. sea salt
1 cup (8 oz) unsalted butter, softened (226 g)
1 ⅓ cup Monk Fruit Sweetener with Erythritol (Granular)
5 eggs, room temperature
1 tsp. pure vanilla extract
Preheat the oven to 325°F (165°C/140°C fan, Gas Mark 3).
Melt butter in a large cast iron pan over medium heat. Be careful not to burn the butter. Add brown sugar and stir until mixed. Remove from the heat. Add vanilla, honey and salt. Stir to combine.
Add the fruit to caramel mixture - fit as much as you can inside. (I used about 1½ lbs of kumquats, and squeezed them all in. About half-way through baking, the syrup bubbled up and spilled out onto my oven floor. Smoke was everywhere. So, you can either place the kumquats in just one layer, or you could take your chances and maybe place a cookie sheet on the rack below the pan to catch any over flow.)
Make the Batter:
Put softened butter and sugar in a large bowl and beat until fluffy. Add eggs one at a time, beating on high. Add vanilla.
In a separate bowl, sift together dry ingredients. Add to wet ingredients and mix on low speed until combined. Carefully spoon or pour batter over kumquats, taking caution not to disturb the fruit. Carefully smooth the batter.
Place cake in oven on the middle rack. Bake for about 1 hour, checking after 45 minutes. Test the cake with a toothpick, making sure it is cooked in the middle. Take a butter knife and loosen edges along the pan. Put cake on a wire rack and let it cool for about 30 minutes.
Put a large platter face down over cast iron pan and flip.
Makes 8 servings.