Sift the flour and the baking powder into a separate bowl. The flour should be sifted necessarily - so it is oxygenated, and the dough becomes airy. If you have time, it is even better to sift the flour twice.

STEP 4: Continuing to beat the eggs, now on low speed, in batches add the sifted flour to the batter. If you beat at high speed, the dough may shrink a lot and lose its fluffiness, because the longer the eggs are beaten, the denser they become, and the more oxygen escapes from the mass. You can also use a spatula, but a mixer will still mix the dough better and more evenly.

STEP 5: The dough should turn out like thick sour cream. But there should still be air bubbles in it, though not as many as before adding the flour.

STEP 6: Wash the apples, peel them, remove the core, and cut into medium sized pieces. I didn't peel, because my apples are thin and I have nothing against peeling))

STEP 7: Sprinkle the prepared apples into the batter and mix everything gently with a spatula.

STEP 8: Line a mold (20-22 cm) with parchment and grease the bottom (but not the walls!) with butter. Place the dough in the mold and flatten. If desired, sprinkle a thin layer of sugar evenly over the dough. I didn't do this, as the dough was already sweet. Bake the quiche in a preheated 180°C oven for about 40-50 minutes. Leave the oven door closed for the first 25 minutes, otherwise the cake will fall over. Check the readiness with a wooden skewer - it should come out dry

STEP 9: Take the finished quiche out of the mold, cool slightly, and serve it in portioned slices. Bon appetit!