Add all Pierogi dough ingredients into a bowl and mix it thoroughly. If you use a mixer, make sure to mix for about 5 minutes until the dough becomes smooth and soft. Alternatively, knead by hand on a clean surface for approximately 8 minutes. If required, add a tablespoon flour at a time until the dough starts forming into a smooth ball. Cover the dough and refrigerate until ready to use.
To make the filling, simmer the potatoes on medium heat until the potatoes are tender and set aside to cool down. Next, crumble the potatoes in little pieces into a bowl. Add ground meat, salt, (optional - pinch of pepper), diced onions, and the Roasted Garlic Kraut to the bowl and stir until well incorporated.
Start rolling the dough out in batches on a floured surface.
Use an inverted glass or scone cutter ( 3-4 inches in diameter) and cut out circles of the dough.
Place a filled tablespoon of the the filling onto one of half of the circle and then fold the other half over.
Gently press together the edges to seal the Pierogis.
Add the Pierogis in a cooking pan or pot with boiling water and cook for about 5 minutes.
