Preheat oven to 200c or 400f
Place sweet potato in an oven proof dish, drizzle with a little olive oil and sprinkle with paprika and sumac to coat. Bake in the oven till softened.
Add the chick peas, sweet potato, fromage frais, juice of a lemon, cumin, paprika, garlic, tahini paste and a little black pepper to a blender and blend until you have a smoothish paste. Add some of the reserved chick pea liquid until hummus is to a consistency you like.
Serve with vegetable crudites or crackers.
The hummus should keep for approx 1 week in an airtight container (if it lasts that long)