• Preheat your oven to 140°C / 285°F.

Preliminary preparations

• Separate the whites and yolks into two different bowls. Weigh the egg white and yolk and check that you have 220g in total. If necessary, adjust the quantities of the other ingredients a little.
• Weigh the butter, cut it into cubes and put it to melt in a bowl in the oven. You can also melt the butter in the microwave or in a saucepan, the oven should then be at 140°C.

Start preparing the dough

• Add the sugar to the egg yolks and whisk them until the mixture turns white. Add the flour, a pinch of salt and the flavor of your choice (a little vanilla or cinnamon, the finely grated zest of an organic lemon, a little amber rum or calvados). Mix.
• When the butter is melted, add it and mix again. Increase the oven temperature to 180°C / 350°F.

Add the apples

• Peel and core the apples. Cut them into quarters and grate them. Add the apples
• Add the grated apples to the dough and mix them.

Add the egg whites

• Beat the egg whites and gently incorporate them into the mixture.
• Grease a loaf pan with butter, add a tablespoon of flour, and tap to coat on all sides. Pour in the cake batter.

Bake

• Bake in the oven for about 40 to 45 minutes. Insert a knife to check if the cake is well-cooked; it should come out dry.