Place all dough ingredients in a stand mixer or large mixing bowl and knead with a dough hook or by hand for about six minutes until smooth and elastic. Transfer the dough to a lightly oiled bowl and cover; allow to rest for one hour.

Place cashews in bowl and cover with boiling water and let soak for 30 minutes.

Boil some water in a large pot and add in potatoes until fork-tender, about 15 minutes.

Strain and place the potatoes back in pot and mash with a potato masher.

After thirty minutes have passed for the cashews to soak, place cashews, milk, garlic, nutritional yeast and portion of the onions into a high-speed blender or food processor until smooth.

Mix into mashed potatoes until creamy and smooth. Add salt and pepper to taste.

Once the dough has rested, split it into quarters. Transfer one of quarter to a lightly floured surface and roll to out until thickness of ravioli dough and cut into three inch circles with drinking glass or pastry cutter. Reroll the dough as needed and continue with all quarters.

Place one tablespoon of the filling onto each dough circle, then fold in half and seal tightly to form a dumpling. Apply a bit of water if you have trouble sealing the dough.

Bring a large pot of water to a boil and add the pierogies (work in batches if it gets too crowded). Cook the pierogies for three or four minutes, until they float, removing each one with a slotted spoon and transferring to a plate as it begins to float.