The classic recipe charlotte:
1 cup flour
1 cup of sugar
4 eggs
0.5 tsp baking powder or baking soda, slaked vinegar (I replace soda baking powder in the same number ve)
4-5 apples (apples charlotte is never too much, you can add a couple more), it is better to take the sour-sweet apples, with Antonovka or Glory winner always turns out great.
You can add them to the dough vanilla sugar, zest of orange or lemon and other fruits, whatever you like.
In a bowl, beat eggs with sugar.