Preheat oven to 350ºF (180 °C). Butter and flour a 9-inch (23 cm) springform cake pan.

In a mixing bowl or stand mixer, combine flour, baking powder, sugar, butter, and salt. Mix on low speed until mixture resembles fine breadcrumbs—not overmixed.

Add eggs, yogurt, vanilla, and lemon zest. Mix on medium‑low speed for 1–2 minutes until just combined.

Gently fold in the apple pieces, reserving a few slices to scatter on top if desired.

Transfer the batter to the prepared pan and smooth the top. Sprinkle the extra tablespoon of sugar over the apples.

Bake for about 50 minutes, until the cake is golden, firm to the touch, and a skewer inserted into the center comes out clean. If the top browns too quickly, tent with foil in the final minutes.

Remove from the oven and cool in the pan for 10 minutes. Then release springform and cool completely on a wire rack.

Once cooled, store the cake in the refrigerator in an airtight container. Serve at room temperature, optionally dusted with confectioner’s sugar or with whipped or mascarpone cream.