Mix yeast with water and pinch of sugar and set aside until it bubbles, about 5-10 minutes.
Mix eggs, sugar and butter until smooth; add sour cream, yeast and lemon zest.
Stir in flour and salt a little at a time until everything is incorporated.
Knead dough on a floured surface then place in a bowl, cover and let it sit in a warm place until doubled in size - about 90 minutes.
While dough is rising mix together filling ingredients and chill until dough is ready.
Once dough has doubled, punch it down and divide into two pieces.
Roll dough in a 9”x13” rectangle.
Spread half of the filling mixture over the dough, leaving a 1” border.
Starting at the long end, roll dough tightly then join ends.
Place cake on a cookie sheet that has been covered with parchment paper. Cover cake with plastic wrap and a towel. Set in a warm place and let it rise for about 30-40 minutes.
Repeat with remaining dough.
Preheat oven 350 F.
Bake for 25-30 minutes. Cool cakes completely on wire racks.
Mix together ingredients for icing.
You can use store bought colored sugar or make your own using 2 c. granulated sugar and food coloring.
Spread icing over cooked cakes and decorate with colored sugar.
