1. For the dough: Add the first 6 ingredients, through the salt, to the Food Processor Work Bowl fitted with the Multi-Use Blade and secure the lid. Press start and allow to run for 15 seconds. Stop the machine, remove the lid, and scrape the sides of the container. Secure the lid, press Start and allow the processor to run for an additional 10 seconds. Remove the dough from the work bowl and wrap in saran wrap, refrigerate for 1-2 hours or until well chilled.
2. For the filling: Place all the remaining ingredients into the Vitamix container in the order listed and secure the lid. Start the blender on its lowest speed, then quickly increase to its highest speed. Blend for 30-45 seconds, using the tamper to press the ingredients into the blades, or until smooth or desired consistency is achieved. Chill the mixture.
3. Once the dough is well chilled, remove from the refrigerator and place on a lightly floured surface. Roll to 1/8" inch thin and cut with desired size cutter (we used a 3" round.) Repeat rolling and cutting until all of the excess dough has been used. You should end up with 20-25 rounds. Fill each with 2-3 teaspoons of sweet potato mixture.
4. Secure the pierogis with a touch of water around the edges of the pierogi dough, folding in half over top of the sweet potato mixture, and gently working from the center of the dumpling outward, press down and pushing any excess air out of the pierogi as you go. Apply a little pressure on the outer rim of the dough to fully secure. Remove to a lightly floured sheet tray.
5. Cook as desired, or freeze and share as a gift this holiday season.