150 grams sourdough, crust removed, torn into small pieces
¼ cup (40g) pine nuts
½ teaspoon ground nutmeg
¼ cup (60ml) extra virgin olive oil
Preheat oven to 200°C/400°F.
Place one sweet potato on an oven tray. Bake for 1 hour or until tender; cool. Reduce oven temperature to 160°C.
Meanwhile, peel remaining sweet potatoes. Using a mandoline or V-slicer, cut sweet potatoes lengthways into 3mm thick slices. Trim slices into 6cm x 12cm rectangles; you will need 36 rectangles.
Bring a large saucepan of water to the boil; season with salt. Add half the sweet potato slices, boil for 1½ minutes or until softened. Remove from pan with a slotted spoon; place on a tray to cool. Repeat with remaining sweet potato slices.
When cool enough to handle, remove skin from baked sweet potato. Place sweet potato flesh in a processor with ricotta; process until smooth. Transfer to a large bowl. Stir in egg, green onion, herbs and half the parmesan. Season.
Grease a 4-litre (16-cup) shallow ovenproof dish (or two 2-litre (8-cup) shallow ovenproof dishes). Place 1 heaped tablespoon of filling mixture at the short end of a sweet potato slice; roll to enclose filling. Place, seam-side down, in dish. Repeat with remaining sweet potato slices and filling mixture, until dish is filled in a single layer.
Combine sourdough, pine nuts and nutmeg in a medium bowl with remaining parmesan and 2 tablespoons of the oil. Sprinkle mixture over sweet potato cannelloni.
Bake for 15 minutes or until top is golden and crunchy.
Serve sweet potato cannelloni topped with extra parsley and drizzled with remaining oil.