FOR THE DOUGH:
In a large mixing bowl, combine the sour cream, flour, butter, 2 whole eggs, egg yolk, 2 teaspoons salt and olive oil. Knead the mixture into a soft dough. Divide the dough in half and cover for 10 minutes. On a floured surface, roll each half of the dough into a thin circle, 1/4-inch thick. Cut the dough using a 3-inch circle cutter.
FOR THE FILLING:
Season the beef with salt and pepper. In a sauté pan, render the ground beef for 3 minutes. Remove from the pan and drain on a paper-lined plate. In a mixing bowl, combine the cheese, ground beef, shallots, garlic, green onion and egg. Mix well. Season with salt and pepper.
Place 1 tablespoon of the filling in the center of each circle of dough and fold over. Press and seal into half-moon shapes. Use a little water to seal the pierogi's. In a pot of boiling, salted water, cook the pierogi for 8 minutes, or until they float. Remove from the water and drain.
In a sauté pan, melt 2 tablespoons of the butter. Sear the pierogi for 2 to 3 minutes on each side, or until they are golden brown. Remove from the pan. The pierogi will need to be sautéed in batches.
Arrange the pierogi's on a platter. Garnish with parsley and serve with sour cream.
Yield: 10 servings