Instructions

1. Add yeast to a 1/2 cup warm milk (110F) and sprinkle with teaspoon of sugar. Leave until bubbled. 
2. Sift flour.
3. Pour remaining 2 cups of milk (heated to 110F) into a mixer bowl.
4. Add activated yeast, remaining sugar, sour cream, eggs and 2 cups of flour.
5. Mix and then add salt.
6. Gradually add the rest of the flour and mix until soft dough forms.
7. Transfer the dough onto a floured surface and knead to form a ball.
8. Then transfer the dough into a lightly greased bowl and let it rise until it is double in size.
9.  Divide the dough into 5 parts.
10. Knead each to form a ball.  Let it rest for about 15 minutes.
11. Using a rolling pin stretch one ball to a circle (about 10″)
12. Take one piece of butter, and smear over the top. Move aside.
13. Do the same with another ball and put it over the first one.  Repeat with the remaining balls.
14. The last one should not be buttered but instead, put over a stack of four buttered circles, stretch a little using your fingers, and tuck under to form a ball. Cover and let this rest for 15 minutes.
15. With a rolling pin stretch dough into a big circle. Cut it up into 16 triangles. 
16. Roll each to form a croissant. 
17. Line 12 croissants in a round 12-inch (30cm) baking pan  and put the last 4 into the middle, placing them so that one end is on the bottom of the pan and the other is up.
18. Brush with egg yolk mixed with 1 teaspoon of water. Sprinkle with sesame seeds if you wish.
19. Bake on 375F for 30-35 in a convection oven (400F for 35-40 min. in conventional oven).
20. Brush with melted butter.