Bring a large pot of salted water to a boil. Add the potatoes, cover, and reduce to a simmer. Boil until you can easily pierce a potato with a fork. Drain the water out and let them cool. (I put the whole pot, covered, just outside of my front door and they cooled off quickly).
In a medium frying pan, add grapeseed oil and onion, and sautee on medium heat for about 6 minutes until the onion is translucent.
Once the potatoes are cool, mash them. Add the cooked onions, coconut yogurt, Core and Rind Rich and Smokey Cashew Cheesy Sauce, salt and pepper. Stir until well combined.
When your dough and filling are both ready, flour a clean counter surface with the gluten-free flour blend. Remove the ball of dough. Cut it in half, and then half again, creating 4 smaller pieces.
Line a cookie sheet with parchment paper. It's even better if you can prepare 2 cookie sheets. Have your second beaten egg in a bowl handy.
Take one piece, mold it into a ball, and then using a rolling pin, flatten out the dough until it's about 1/8 inch thick.
Use a cup, or a clean old tin can (we have one clean and labeled as the pierogi cutter, sitting in our pantry), to cut round circles out of the dough.
Take the circle in one hand, and with the other fill the middle of the dough with about 1 tbsp. of filling (use your judgement as to how much is appropriate - it will all depend on how big your circles were cut).
If you prepared a second beaten egg, this is where it comes in handy. Brush the inside edges of the circle with some egg, fold over the dough in half (be careful not to try and stretch the dough, it will tear), and lightly pinch the edges together.
Place the formed pierogi on the parchment paper. Repeat the steps above until you have formed all of the pierogies. As you need more dough, roll out another quarter.
Bring a medium to large pot of water to a boil and reduce to a light boil. Add about 1 tbsp. of olive oil to the water and a few pinches of salt.
Place about 6 pierogies in the water, and allow them to boil until they float to the surface (about 3 minutes). Scoop them out with a slotted spoon (to allow excess water to drip out) and place them on a plate with paper towel. Transfer to second prepared cookie sheet. Repeat until you have boiled all of the pierogies.
If you want to freeze the pierogies to enjoy later, put the whole cookie sheet into the freezer for about 1 hour. And then transfer the pierogies into ziplock bags. I like to portion 5 per bag, for individual servings.
TO COOK the FRESH pierogies: Heat a medium sized pan with 1 tbsp. oilive oil or butter. When hot, add the pierogies, immediately starting to move them around so they don't stick. Saute on each side for about 2 minutes, until a golden crispy layer has formed.
TO COOK the FROZEN pierogies: Unthaw, and repeat steps above.
Enjoy with a dollop of unsweetened coconut yogurt, and/or sauteed onions.