Apple and walnut cake (without oil or butter)

I saw chef Persegani make this recipe on an episode of ‘Casa Alice’. It is delicious and full of flavour!I peel the apples and cut them into cubes.
I put them in a bowl and add the juice and grated zest of a lemon to flavour them and prevent them from browning.
I soak the raisins in the liqueur or in lukewarm water.
I roughly chop the walnuts.
I separate the egg yolks from the whites. I whisk the yolks with the sugar and a pinch of salt.
They should become pale, thick and fluffy. I whisk the egg whites until stiff. I sift the flour with the baking powder. I put the flour and whisked eggs in a very large bowl to make it easier to combine all the ingredients.
I add the apples, walnuts and drained raisins. Now use your hands to mix thoroughly, making sure all the ingredients coat the apples, even though the mixture will look loose and uneven. That is how it should be. I add the egg whites.
I mix gently, still using my hands. This step is essential: stirring with a spoon deflates the egg whites, making the mixture too loose and greatly increasing the baking time. I add a dash of grappa. I pour the mixture into a 28 cm tin lined with baking parchment and bake at 160°C for 50/60 minutes. At the end of baking, insert the tip of a knife into the centre. If it comes out clean, the cake is cooked; otherwise, bake a little longer. This will depend on your oven. When the cake is lukewarm, dust it with icing sugar. This makes a very large cake, but a very good one too. You can halve the quantities if you wish.