Separate eggs for egg yolks and egg whites. Set aside.
Wash, peal and cut fresh apples to small cubes.
In the frying pan add apple cubes and cinnamon powder, cover with the lid and cook for about 10-15minutes. Turn off the heat and let it cool.
In the mixing bowl, whisk flour, baking powder and powdered sugar. Set aside.
In the mixing bowl of stand mixer, sift flour mixture. Add cubes of unsalted butter and egg yolks. Using pedal attachment, mix untill all combine.
In the other mixing bowl add egg whites and salt. Whisk for about 30 seconds. Add granulated white sugar and whisk for about 5minutes over medium speed. You need to make french meringue.
Add lemon juice intofrench meringue and whisk again for 15-20 seconds.
Line up baking pan with parchment paper.
Add about 3/4 of the dough intopan and press lightly with the fingers.
Spred cooked apples over dough with the help of spatula or spoon.
Add french meringue and spread over apples.
Top with the remaining dough.
Bake for 40-45 minutes at 350 F degrees (180C) or untill top of the cake will be light brown.
Remove cake from the oven and let it cool to room temperature.
Cut into squares and enjoy!
Notes
Eggs should be room temperature. Unsalted butter can be straight from the fridge.