Step 1: Mix three spoons of lukewarm milk with one teaspoon of sugar and yeast in pot.
Step 2: Mix warm milk, raw butter, sugar, a tablespoon of salt and warmed flour in large bowl. Stir well. Add leavened yeast and 2 yolks. Use ladle to batter mixture thoroughly for 20 to 30 minutes.
Step 3: Dust dough with flour, cover it with a bowl. Place somewhere warm to rise.
Step 4: When dough rises, sprinkle board with flour, roll out dough to about 1 cm thick and cut off corners to make a rectangle. Add filling.
Filling and finishing:
Step 1: Whip raw butter until foamy; add 2 tablespoons of sugar, 3 yolks and stiff egg white foam. Stir well.
Step 2: Add chopped tarragon leaves. Stir well.
Step 3: Spread filling evenly on dough.
Step 4: Roll into a compact roll and place into a greased round potica baking tin. Roll ends must converge well. If the roll is too long, cut to get the right size. Do not throw away the cut-off sections; bake them in separate smaller rectangular baking tins.
Step 5: Cover potica with tablecloth and put somewhere warm to rise.
Step 6: Brush potica with beaten egg before baking. Bake at 180°C for about 45 minutes. Then lower the temperature and bake another 25 minutes.
Step 7: Turn potica upside down and let it cool. Top with powdered sugar and serve wedgy slices.
Source: Janez Bogataj (2007): “Tasting Slovenia”, National Geographic