Cut butter into chunks. Place it in a bowl and add flour. Start mixing everything together until you see "flour crumbs".
In a separate bowl, mix cottage cheese, egg, sugar, baking powder, salt, oil and amaretto.
Combine dry and wet mixtures and quickly make a dough. When ready, divide it into 4 parts and cover each with plastic. Place in a fridge for an hour.
While the dough is resting, prepare the walnut filling. Dry roast walnuts on medium heat for about 7 minutes, until they are golden. Then crush them into small pieces. You can use a zipper seal bag and a rolling pin or a food processor for a finer texture.
In a bowl, mix walnuts, 2 egg whites and sugar.
Remove the dough from the fridge. Roll each piece into a rectangular shape, cut off the edges to make the straight sides. The sheet should be very thin. Divide it into 6 squares and then divide each square into 2 triangles.
Use your fingers to adjust the dough into a triangular shape. Place about half a teaspoon of walnut filling on the bottom of the triangle and roll it up. Make sure the tip of the triangle is on the bottom of the roll.
Place all rolls with walnut filling on a baking sheet. Use kitchen brush to top each with some egg yolk. Bake at 400 F for 15 to 20 minutes depending on your oven.
Remove the rolls from the oven and let them cool. Place them on a plate, top with some powdered sugar and enjoy with a cup of a tea!