Preheat the oven to 350°F (175°C). Grease a 9-inch springform pan and line the bottom with parchment paper.

In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.

In a large bowl, beat the butter and sugar until light and fluffy, about 2–3 minutes.

Beat in the eggs one at a time. Add the vanilla, almond extract, lemon zest, and lemon juice, mixing until combined.

Gradually mix in the flour mixture on low speed just until combined. The batter will be thick.

Spread the batter evenly in the prepared pan.

Working with one apple at a time, peel, halve, and core the apple, then place each half cut-side down.

Using a sharp knife, cut thin slices (about 1/8 inch thick) crosswise without slicing all the way through, so the slices stay attached at the bottom. Then slice each half into two pieces along the center cut.

Brush the cut surfaces with a bit of lemon juice to prevent browning. Repeat with remaining apples.

Gently press the apples into the top, sliced side up. Sprinkle turbinado or Demerara sugar over the apples for a light crunch and caramelized finish.

Bake for 45–50 minutes, or until the top is golden and a toothpick inserted in the center comes out clean.

Let cool in the pan for 15 minutes, then remove the sides of the pan and cool completely. Garnish when serving.