Grease the bottom of a 9x13 inch baking pan, and layer sweet potato slices the way you would layer noodles for a lasagna. Spread about half of the quinoa mixture and top with some of cheese. Repeat with another layer of sweet potato slices, meat & cheese and then finally top with a final layer of potatoes and a generous amount of cheese. Cover the pan with foil. Bake until sweet potatoes are cooked through, about 60 minutes. Remove the foil and bake for about 15 more minutes, until the cheese is bubbly. Remove from the oven and rest for about 10 minutes before cutting. Garnish with freshly chopped cilantro, chopped avocado & a dollop of sour cream.