Russian Piroshki (Stuffed Fried Dough Pockets)

In a large bowl, combine warm milk, yeast, and sugar. Let it sit for 5-10 minutes until foamy. Add flour, salt, egg, and melted butter. Knead the dough until smooth and elastic, about 8-10 minutes. Cover with a clean kitchen towel and let it rise in a warm place for 1-1.5 hours, or until doubled in size.

While the dough is rising, prepare the filling. In a skillet over medium heat, sauté the finely chopped onion in a little oil until translucent, about 5 minutes. Add the ground meat and cook, breaking it up, until fully browned, about 8-10 minutes. Season with salt and pepper to taste. Remove from heat and stir in the mashed potatoes and chopped dill (if using). Let it cool completely.

Once the dough has risen, turn it out onto a lightly floured surface and knead briefly. Divide into 10-12 equal pieces. Roll each piece into a circle about 10-12 cm (4-5 inches) in diameter. Place a tablespoon of filling in the center of each circle. Fold the dough in half and firmly pinch the edges together to seal the pocket. Repeat with the remaining dough and filling.

In a deep skillet or pot, heat ample vegetable oil over medium-high heat (about 170-180°C / 340-350°F). Carefully place a few piroshki into the hot oil, making sure not to overcrowd the pan. Fry until golden brown on both sides, about 3-5 minutes per side. Remove from oil and place on a paper towel-lined plate to drain excess oil. Serve warm.