Unsalted butter, for greasing dish
2 tablespoon water
1 (1/4) cup sugar, divided
8 plums, sliced in 1/2 inch rounds
2 large eggs
Juice and zest from 1 orange (2 teaspoons zest, plus 1 tablespoon juice)
2 teaspoons pure vanilla extract
1/3 cup olive oil
1 (1/4) cup self-rising flour
1 teaspoon freshly ground nutmeg
1 teaspoon table salt
Confectioners sugar, (optional for garnish)
Preheat an oven to 350 degrees. Grease a 9-inch round baking dish with butter, lay the plums in the dish, cut side down.
In a small saucepan, bring to a boil the water and 1/2 cup sugar over high heat until the sugar turns amber brown, about 360 degrees F on a candy thermometer. Swirl the pan but don't stir. Pour evenly over the plums.
In a mixing bowl, whisk the eggs and remaining sugar on medium speed until light and fluffy. Add the orange zest and juice, and the vanilla. Return to mixer and beat on medium speed until well combined. Slowly stream in the olive oil and mix until light and smooth. Sift together the flour, nutmeg and salt. Using a rubber spatula or wooden spoon, stir in the flour mixture until well combined and flour dissolves.
Pour the cake batter evenly over the plums and bake for 30 to 40 minutes, until a toothpick comes out clean. Cool for 15 minutes, then invert the cake onto a flat surface. If a plum sticks, ease it out and replace it in the design on top of the cake. Serve warm or at room temperature.
Do not over mix the batter, otherwise the cake may be tough. Use a good quality olive oil for best results. You may need to shake the baking dish a bit more than usual until the cake comes out, just be patient...