2 packages dry yeast
1 teaspoon sugar
6 cups flour (5 cups to start, adding additional flour as needed)
2 cups warm milk
1/2 cup softened butter
3 egg yolks
1/2 cup sugar
1 tablespoon dark rum
1 tablespoon. vanilla
Zest of 1 lemon
Pinch of salt
1 cup chopped fresh tarragon leaves
1/2 cup butter
2/3 cups sugar
3 eggs, separated
5 tablespoons breadcrumbs
1 cup Marscapone cheese
2 tablespoons cottage cheese
Mix softened butter, sugar and egg yolks until the sugar is well dissolved and mixture is frothy. Set aside. Warm the milk, mix in salt, lemon peel, vanilla and rum; add to the butter mixture. Form the dough out of the 5 cups of flour, yeast and milk mixtures. The trick is not to pour in all the milk mixture immediately; use about 3/4 to start with, then add more as the dough forms.
Mix the dough until smooth and elastic. Then keep adding flour as needed, mixing with a wooden spoon until the dough can be handled without sticking. Place dough on floured board and knead for about 15 minutes, adding flour as needed to make a smooth, pliant and non-sticking dough. Place dough in a well-greased bowl; turn dough upside down to grease top. Cover and let rise in warm place until doubled in bulk. While dough is rising, prepare filling.
Mix softened butter, sugar and egg yolks until the sugar is dissolved. Add Mascarpone and cottage cheese. Fold in beaten egg whites, and breadcrumbs.
Roll out dough on table covered with a tablecloth sprinkled with flour. The dough should be rolled thin enough to see the tablecloth pattern through the dough.
Spread filling evenly over entire dough surface. Then spread chopped tarragon over the filling. Start rolling up dough by hand, jellyroll fashion, stretching dough slightly with each roll. Keep side edges as even as possible. Continue to roll by raising the cloth edge slowly with both hands so the dough rolls itself. Dust away any excess flour on the outside of the dough with a pastry brush as you roll. Prick roll with a toothpick as needed to eliminate air pockets.
With the edge of a spatula, cut off each end of roll to make it the length needed to fit around the inside of large baking pan, angle food cake pan or Bundt cake pan, being sure to arrange the seam where the roll ended against the center, to form a full circle. If you have a two-piece angel food cake pan, it is easiest to roll the loaf onto and around the bottom plate of the pan, and then lower this into the body of the pan. Cover with a cloth and let rise in a warm place until double in volume. Bake about 1 hour at 325 degrees.
For a shiny crust, brush top before baking with 1 egg beaten with 1 tablespoon milk, or brush top with melted butter when taken from oven.
Let stand at least one hour before removing from pan. Loosen sides and bottom with knife. Turn onto wire rack to remove, then turn over again onto another wire rack to cool right-side up. Once completely cool, turn upside-down on a cake plate and sprinkle with powdered sugar.
If you have trouble with the warm potica settling with handling or once you turn it over, an alternative is to leave it right-side up in the pan until completely cool. You can even remove the outer ring of the angel-food cake pan, and let it cool completely that way before turning it over onto a cake plate. Or you can just serve it right-side-up on the base of the pan!