3 potato pirozhki with Recipes

yeast, sugar, lukewarm milk (105 - 115 f), unsalted butter, melted and at room temperature, egg, beaten, salt, all-purpose flour, potatoes, olive oil, onions, chopped (about 3/4 cup), sour cream, horseradish, dill, salt and pepper to taste, egg yolk, milk

all-purpose flour, double-acting baking powder, salt, cold unsalted butter, cut into bits, egg yolks, sour cream, cold water if necessary, russet (baking) potatoes, unsalted butter, onion, chopped fine, caraway seeds, vegetable oil, chopped cabbage, sour cream, water if necessary, chopped fresh dill, an egg wash made by beating 1 large egg with 1 tsp water