All year round, there’s a citrus fruit in season. In September, it’s the Valencia varietal, which is typically used for making orange juice. Make a classic Italian dessert that melds the flavors of sweet oranges, robust almonds, and rich olive oil. This cake calls for a light homemade organic Orange Whipped Cream for dessert.
Combine 2 cups of the sugar to equal parts water in a medium saucepan. Bring the mixture to a boil over medium-high heat. When the sugar dissolves, add the whole oranges and lemon to the mixture. The mixture should cover at least ⅔ of the fruit. If it doesn’t, add more sugar and water in equal parts. Cover the pan and lower heat to a simmer. Cook, stirring occasionally, until the fruit can be easily pierced with a toothpick, around 40 minutes. Transfer the cooked fruit to a plate, and the syrup to a jar (the syrup will be used later to flavor the whipped cream).
Put almonds in the bowl of a food processor and pulse until finely ground. Transfer to a bowl, and whisk in the flour and baking powder. Set aside.
Oil a 9-inch-round by 3-inch-tall cake pan with some olive oil. Position a rack in the center of the oven, and heat to 350 degrees.
Cut the fruit into quarters and remove seeds and large pieces of fruit membrane. Put fruit in the food processor and pulse until smooth.
Put the eggs and salt in a bowl, and beat on medium-high with a whisk attachment until light and foamy, around 3 minutes. Gradually add remaining 1 ½ cups sugar, and beat until thick and white, around 4 minutes more. Add olive oil with whisk attachment running. Add the puréed fruit and mix just until blended. Gradually fold in the flour mixture until smooth.
Pour the batter into the greased pan. Bake until the cake is dark golden brown, about 1 hour 10 minutes. Let cool for 10 minutes, and run a knife around the edges to loosen the cake. Turn out onto a rack, and cool completely.