1 Preheat an oven to 375°F (190°C). Generously
butter a 9-inch (23 cm) round cake pan with 2 inch (5 cm) sides.
2 In a microwave, melt the butter. Pour 6 Tbsp (3 fl oz or 90
ml) of it into a small bowl or cup and set aside. Add the apple slices
and the remaining butter to a large frying pan and cook on low heat,
stirring occasionally, until the apples are tender, about 10 minutes.
Remove from the heat.
3 In a small bowl, stir together the flour, baking powder, and
salt. In a large bowl, beat the whole eggs and egg yolk until blended.
Add the 6 Tbsp of melted butter, the vanilla, the granulated sugar,
and the lemon zest. Stir in the flour mixture and the apples. Spoon
into the prepared pan, smoothing the top.
4 Bake until browned, 30-35 minutes. Transfer to a wire rack
and let cool in the pan for 5 minutes. Invert the cake onto a plate and
lift off the pan, then invert the cake again onto the rack and let cool
5 (Optional) Just before serving, place confectioners' sugar
in a small sieve and dust the top of the cake.