1-First, preheat your oven to 350°F (175°C) and grease a 9-inch (23 cm) round cake pan with butter, lining the bottom with parchment for easy release. Peel, core, and slice 4 medium apples into even wedges to ensure uniform cooking, and place a rimmed baking sheet nearby to catch spills.

2-Next, make the caramel topping by melting 1/2 cup (115 g) unsalted butter in a small saucepan over medium heat, then stir in 2/3 cup (135 g) packed brown sugar until it simmers into a glossy mixture for 2 to 3 minutes. Remove from heat, add a pinch of salt and 1/2 tsp cinnamon, then pour and spread it evenly in the prepared pan.

3-Arrange the apple wedges in a single layer over the caramel, fanning them neatly and overlapping slightly for a pretty pattern.

4-Then, mix the cake batter by whisking together 1 1/2 cups (180 g) all-purpose flour, 2 tsp baking powder, 1/2 tsp salt, 1 tsp ground cinnamon, and 1/4 tsp nutmeg in a bowl. In another bowl, cream 1/2 cup (115 g) softened butter with 1 cup (200 g) granulated sugar until light, beat in 2 large eggs one at a time, and stir in 1 tsp vanilla and 1/2 cup (120 ml) milk, alternating with the dry ingredients.

5-Spoon the batter over the apples, smooth it out, and bake in the preheated oven for 40 to 50 minutes until golden and a toothpick comes out clean. After baking, let it cool for 10 to 15 minutes, then invert onto a plate.