Crack the nuts and recover the walnut kernels. Using a knife, crush them coarsely.
Peel and dice the apple. In a salad bowl, mix the flour and baking powder, then the apple cubes and the crushed walnuts.
Preheat the oven to 170°C.
Whisk together the soft butter and sugar for 5 minutes. Add the eggs one by one, stirring in completely between each addition. Finally, add the flour/yeast and apple/nut mixture and mix with a spatula or spoon without insisting, just enough to make the flour disappear.
Pour the dough into a cake tin lined with baking paper. Bake for about 40 minutes. Check that the tip of a knife is cooked: it should come out dry.
Unmould within 15 minutes and cool on a wire rack.
For a touch of shine
For a shiny cake, you can coat it when cold with quince or lemon jelly heated in a pan. And for a reminder of the nuts, place some nice kernels on top, which you will make shine with the jelly!
Author: Céline Mennetrier – Photo credit: Aurélie Jeannette