Ingredients:

• 2 cups of flour
• 100 g of unsalted butter
• 150 g of sour cream
• 1/2 cup of sugar
• 1 egg
• 1/2 tsp of baking soda
• 2-3 lemons
• 2 tsp of cornstarch
• 4 tsp of sugar

Instructions:

1. Cut the lemons into pieces and remove the seeds. Blend the lemon pieces in a blender. If the lemon peel is bitter, remove the bitterness.
2. Boil 2-2.5 liters of water in a pot and add the lemon pieces. Boil for about 15 minutes.
3. In a separate bowl, mix sugar and cornstarch, then add the blended lemon mixture. Stir well until the mixture is smooth.
4. Separate the egg white and yolk. In a mixing bowl, combine flour and butter, then add sour cream, baking soda, sugar and egg yolk. Mix well to form a dough and divide into two parts, with one part being larger than the other.
5. On a flat surface, roll out the larger piece of dough to fit the size of the tart pan. Place the dough in the pan and create edges to prevent the filling from spilling out.
6. Pour the lemon mixture onto the dough, spreading it evenly.
7. Roll out the smaller piece of dough and place it on top of the lemon mixture. Brush the surface with whipped egg white.
8. Bake the tart in a preheated oven at 200°C until the top is golden brown.