In a bowl, mix the flour, baking powder and very cold butter cut into cubes.
Using your fingers, incorporate the ingredients; in the end, you should get a dough that resembles wet sand.
In another bowl, mix 50 g of sour cream, 1 egg, 60 g of sugar and 2 g of salt for 4-5 minutes.
Pour the sour cream mixture over the shortcrust pastry, mix with a spoon, then continue to knead gently.
Put the dough in a diagonal shape of 25 cm.
Flatten with your fingers over the entire surface and sides of the tray.
Let the tray cool.
For the filling, add 2 eggs, 100 g of sugar and 20 g of cornstarch, mix until there are lumps, pour in 1 tablespoon of vanilla essence and 350 g of our 15-20% fat sour cream.
Peel the apples and remove the core, slice the apples 2-3 mm thick.
Remove the tray from the refrigerator, place the apples in an even layer.
Pour in the sour cream mixture.
Place the tray in the preheated oven at 180 °C for 50 minutes.
Let the tart cool down a bit. Serve the tart warm or cold.
