Ingredients for the tart dough:
½ cup (110 g) butter, softened
- ½ cup (100 g) sugar 2 cups (230 g) all-purpose flour
- 1 egg
- 2 tablespoons unsweetened cocoa
- Ingredients for the citrus filling:
- 2 cups (440 g) granulated sugar
- 4 large eggs
- ½ cup (1.2 dl) orange juice
- ¼ cup (0.6 dl) lemon juice
- Grated peel of 2 oranges
- 3 tablespoons all-purpose flour
- 1 teaspoon baking powder
Ingredients for the chocolate frosting:
- ½ cup (1.2 dl) heavy cream or whipping cream
- 7 oz (200 g) semisweet chocolate (40-50% cocoa)
- Line the bottom of a springform pan of 9 inches (23 cm) diameter with greaseproof or other non-stick paper and grease the sides of the pan.
- Using an electric mixer, cream the softened butter and sugar.
- Add flour and cocoa powder, and finally the egg.
- Reserve in the fridge for a few hours or more.
- Preheat oven to 350 deg F (Gas mark 4 or 180 deg C).
- Using your fingers, pat down half of the tart dough into the bottom of the springform pan (not the sides); keep the rest frozen until next time.
- Bake at 350 degrees for about 7 minutes.
- For the filling, mix sugar and egg for 2-3 minutes with an electric mixer.
- Add lemon juice, orange juice, grated orange peel, flour and baking powder, and mix well.
- Transfer to the springform and bake at 250 deg F for about 30 to 40 minutes.
- A wooden pick inserted in center should come out clean.
- Using a knife, loosen carefully the cake from the sides of the springform pan.
- Let the tart cool to room temperature in the pan.
- For the chocolate frosting, heat the cream almost to a boil, add chopped chocolate, and stir until smooth.
- Let it cool until it thickens.
- Spread the chocolate frosting evenly on top and sides of the tart.
- Instead of lemon, you may use 2 limes and grated lime peel, and reduce the amount of orange peel accordingly.