Poke holes in the sweet potato, wrap it in foil, and roast it in the oven for 60 minutes or until very soft. When sweet potato is finished roasting, allow it to cool then carefully scoop the flesh out the skin and place it in a blender (you can also leave the skin on).
In a medium skillet, heat olive oil to medium and saute the onion until transluscent, about 10 minutes.
Add the garlic, ginger, curry powder, turmeric, sage, red pepper, and sage, and saute another 2 minutes.
Add this mixture to the blender with the sweet potato, along with the chicken stock and coconut milk.
Blend until smooth.
Add the soup back into the saute pan (or large pot) to heat it to desired temperature.
Serve with cooked quinoa, fresh chopped cilantro, and plain yogurt (or sour cream).