Use a large bowl and pour the lukewarm milk, yeast, sugar and 1 tbsp flour and stir with spoon. Leave to rise until frothy for 10 minutes.
Then add into the bowl 3 cups of flour, baking powder, vegetable oil, salt, egg whites and stir well until forming the dough. Then transfer it into a lightly floured cutting board.
Knead the dough for 10 minutes, then place it in a large bowl, cover it and leave it at warm place for about 1 hour to doubled in size.
Preheat the oven to 375F.
Once the dough is ready take it out of the bowl and knead for another 5 minutes and divide into 5 even balls.
Take one piece and roll it out to about the size of a medium round pizza.
Cut the rolled out dough into 8 equal triangular slices, a pastry roller or pizza cutter works great for this.
Divide into 'triangles' and place slightly a tablespoon of the crumbled feta cheese at the widest part of the triangle.
Beginning at the widest point of each slice, roll it toward the narrow tip.
In a baking dish place a baking sheet and start adding the ready to bake. Repeat until all the dough is gone.
Use a small mixing bowl to whisk the egg yolks and then apply it to each croissant.
You can sprinkle sesame seeds on top of each croissant.
Bake for approximately 20 minutes or until golden brown
Serve them warm and enjoy with tarator.