Twice-Baked Sweet Potatoes with Ricotta

1. Heat oven to 400*F. Pierce potatoes with a fork several times and place on a foil-lined baking sheet. Bake until they're soft when pierced with a knife, about 1 hour. 2. Remove and let cool about 20 minutes. Meanwhile, heat olive oil in a small nonstick skillet and add shallots. Cook until soft and just browning. Transfer to a bowl and set aside. 3. When cool enough to handle, cut potatoes in half, lengthwise. Use a spoon or melon baller to scoop out the flesh, leaving inch around the skin edges for stability. 4. Put all potato flesh into the bowl of a food processor or a blender and process until just smooth, about 20 seconds. (If using a blender, stop occasionally to scrape down the sides.) Add salt, pepper, ricotta, ginger, and brown sugar, and puree until smooth. 5. With a spoon, stir in Parmesan cheese, sage, and cooked shallots. Spoon puree into potato shells, or put the mixture into a large zipper-style plastic bag. Cut off a corner of the bag and gently squeeze mixture into shells. 6. Set oven temperature to 350*F. Sprinkle each potato half with a little Parmesan cheese and sage leaves if desired, and bake until heated through, about 30 minutes. Make-ahead tip Complete steps 1 through 5 the day before, then place potato halves in airtight container and store in refrigerator. Bring to room temperature before baking, or add 10 minutes to the final cooking time.