Adapted from Cooking in the Moment by Andrea Reusing.
You can use any sweet, small orange for this cake, such as tangerines, clementines or satsumas. Be sure to pick out the seeds if you use a seeded variety like I did. The cake is lovely served with a bit of lightly sweetened whipped cream. Oh, and I recommend that you remove the tangerine slices before eating. While they make the cake stunningly bright and pretty, they can be bitter.
For the syrup:
6 small tangerines or other orange of your choice
1 tbs lemon juice
1 cup sugar
For the cake:
4 tbs butter at room temperature
3 tbs good quality olive oil
3/4 cup sugar
1/3 cup semolina flour
2/3 cup all-purpose flour
1 tsp baking powder
1/4 tsp kosher salt
Preheat the oven to 375 degrees and butter an 8 inch round cake pan.
Finely grate the zest of 2 of the tangerines (you want about 1 tbs). Cut them in half and juice them (you want about 1/3 cup of juice). Slice the remaining tangerines into 1/4 inch thick slices. Combine the juice, tangerine slices, lemon juice and sugar in a small saucepan. Bring to a simmer over low heat. Continue to simmer for another 5 minutes, or until the tangerine slices begin to become translucent. Remove the slices with a slotted spoon onto a plate. Continue to simmer the syrup until it has reduced to 1/2 cup, another 5 minutes or so. Set aside.
In the bowl of a stand mixer, beat together the butter and sugar until it is light and fluffy. Add the olive oil and beat for another 2 minutes. Add the eggs, one at a time, until they are fully incorporated, then beat in the tangerine zest.
In a small bowl, stir together the semolina, flour, baking powder and salt. Slowly add the flour mixture to the butter/olive oil mixture with the mixer on low speed, just until the flour is fully incorporated. Pour the batter into the prepared pan and arrange the tangerine slices over the top. Bake for 10 minutes. Reduce the oven temperature to 350 degrees and continue baking the cake until the top is lightly golden and the center springs back when gently touched. This should take another 20-25 minutes.
Let the cake cook in the pan on a baking rack for about 5 minutes. Using a wooden skewer, poke holes all over the cake. Brush the reserved syrup over the cake using a pastry brush. Repeat this two or three times. Let the cake cool completely. Unmold and serve sliced into wedges and topped with whipped cream.