1-Preparing Baked Pirozhki: starts with activating the yeast for a fluffy dough. For more on handling yeast, check out a reliable guide on baking with yeast from a trusted source. Begin by combining warm milk, sugar, and active dry yeast in a large bowl, letting it sit for 5-10 minutes until it becomes foamy. This step ensures the dough rises properly and achieves that soft texture.

2-Next, add the flour, salt, vegetable oil, and beaten egg to the yeast mixture, then mix thoroughly until the dough forms. Knead on a floured surface for 8-10 minutes to develop a smooth, elastic consistency, incorporating the dry ingredients like all-purpose flour, granulated sugar, instant dry yeast, and coarse kosher salt as mentioned. Once ready, place the dough in an oiled bowl, cover with a damp towel, and let it rise in a warm spot for 1-1.5 hours until doubled in size for vegan or gluten-free versions, keep an eye on the time as it may vary.

3-For the filling, sauté chopped onions until translucent, then add ground beef, garlic, and coarse kosher salt with olive oil until fully cooked, and mix in leftover mashed potatoes for extra heartiness. Divide the risen dough into 12 equal parts, flatten each into a circle, add the filling, and seal into half-moon shapes. Arrange on a parchment-lined baking sheet, brush with an egg wash made from an egg yolk mixed with water, and bake at 350°F for 20-25 minutes until golden brown. The total preparation time is about 2 hours, yielding 12 tasty hand pies that can be served warm.