Upside-down pie with carambola

Ingredients:

Topping

• 3 tbsp unsalted butter, plus extra for greasing the pan
• 3 tablespoons light brown sugar
• Juice of half a lemon
• 3-4 small star fruits, cut into 0.5 cm thick stars.

Pie

• 0.5 cup pecans
• 1 and 1/4 cups whole wheat flour
• 1 teaspoon ground cinnamon
• 3/4 tsp baking powder
• 3/4 tsp baking soda
• 0.5 tsp freshly grated nutmeg
• 0.5 tsp coarse salt
• 1/4 tsp ground allspice
• 110 g unsalted butter at room temperature
• 2/3 cup light brown sugar
• 2 large eggs
• 0.5 tbsp. low-fat yogurt

Preparation:

1. Position a rack in the center of the oven and preheat to 350°F (175°C). Grease a 9-inch (22 cm) round cake tin.
2. Topping:
   
   Melt the butter, brown sugar, and lemon juice together in a small bowl in the microwave. Spread the mixture over the bottom of the prepared pan. Arrange the star fruit slices on top, pressing them together and slightly overlapping. Set aside.
3. Pie:
   
   Place the pecans on a baking sheet and toast in the oven for 8-10 minutes. Let cool, then pulse in a food processor until finely ground. Combine the ground pecans, flour, cinnamon, baking powder, baking soda, nutmeg, salt, and allspice. Set aside.
4. Using a mixer on medium speed, beat the butter and brown sugar until light and fluffy, about 5 minutes. Add the eggs one at a time, beating until fully incorporated. Scrape down the sides of the bowl as needed. Reduce the mixer speed to low and add half the flour mixture, then the yogurt, then the remaining flour.
5. Pour the batter into the pan, spread it into an even layer, and tap the pan on the counter a few times to release any air. Bake until golden brown, a toothpick inserted into the pan comes out clean, and the cake pulls away from the sides of the pan, 45-50 minutes. Cool on a wire rack until you can handle the pan, then run a knife around the edge and invert the cake onto a serving platter. Cool completely and serve.