Upside-down cake with oranges in salted caramel

Ingredients:

Pie

• 0.5 cups chopped almonds
• 1 and 1/4 cups premium flour
• 3/4 tsp baking powder
• 3/4 tsp baking soda
• 110 g salted butter, room temperature
• 2/3 cup granulated sugar
• 2 large eggs
• 1 tsp. grated orange zest
• 0.5 cup sour cream
• Sea salt, to sprinkle

Caramel

• 2/3 cup sugar
• 1/4 teaspoon coarse salt
• 1 tbsp salted butter
• 4-5 oranges

Preparation:

1. Cook the caramelCombine granulated sugar, 1/3 cup water, and coarse salt in a large saucepan. Heat over medium heat, stirring until the sugar dissolves. Cook, gently swirling the pan occasionally but not stirring with a spoon, until amber-colored, 8-10 minutes. Brush off any sugar crystals stuck to the sides of the pan with a damp pastry brush. Remove from heat and stir in the butter (the caramel will bubble vigorously). Pour into a 9-inch (22 cm) cake pan, covering the bottom completely.
2. Cut off the tops and bottoms of the oranges. Stand them upright and use a chef's knife to cut away the peel and white pith, following the curves of the fruit. Cut through the membranes and release the segments. Remove the seeds and set the orange segments aside.
3. Preheat oven to 350°F (175°C). Place the almonds on a baking sheet and toast until golden brown, 8-10 minutes. Let cool, then transfer to a food processor and pulse until finely chopped. Place the almond flour in a medium bowl; add the flour, baking powder, baking soda, and coarse salt and stir to combine.
4. Bake a pieIn a large bowl, beat the butter and sugar with a mixer on medium-high speed until fluffy, about 5 minutes. Beat in the eggs one at a time, scraping down the sides of the bowl as needed. Stir in the orange zest. Reduce the mixer speed to low; beat in the flour mixture in three additions, alternating with the sour cream, beginning and ending with the flour. Knead until smooth.
5. Arrange the orange slices in a circle in the caramel pan. Pour the batter over the top and smooth the surface. Bake until the cake is golden brown and a toothpick inserted into the center comes out clean, 40-45 minutes (cover with foil if the top is browning). Transfer to a wire rack and let cool slightly, then run a knife around the cake and invert it onto a platter. Let cool completely. Sprinkle with sea salt.