Method

• 1.
  Preheat oven to 180°C. Line a large baking tray with baking paper.
• 2.
  Place a sweet potato on a chopping board with a chopstick on either side (to help stabilise and give the knife a counterpoint). Use a sharp knife to cut at 3mm intervals, slicing the potato three-quarters of the way through, being careful not to slice all the way through.
• 3.
  Place sweet potatoes on the prepared tray, drizzle with 1/4 cup (60ml) oil and season with salt flakes and freshly ground black pepper. Cover with foil and cook for 45 minutes or until just tender. Remove from the foil, baste the potatoes with the remaining 20ml oil and return to the oven for a further 20 minutes.
• 4.
  Meanwhile, for the walnut pangrattato, place the walnuts, both garlics, capers and anchovies in a food processor and whiz to a paste. Add the parsley and sage, and whiz until smooth. Add the olive oil and lemon zest and juice, and whiz to combine. Finally add the bread and pulse until combined and the mixture has become the size of course crumbs. Season to taste.
• 5.
  Arrange the crumb around the sweet potato on the baking tray and cook for a further 15-20 minutes, until the sweet potato is golden brown and the crumb is golden and crisp.
• 6.
  Meanwhile, for the soused shallots, place the vinegar, sugar, 1 tbs boiling water and 1/4 tsp salt flakes in a small bowl and stir until sugar dissolves. Add the eschalot, stir to combine and set aside until ready to serve.
• 7.
  To serve, arrange sweet potato and walnut pangrattato on a serving plate, scatter with extra chopped parsley, top with the soused shallots and drizzle with extra olive oil. Season with salt flakes and freshly ground black pepper. Crumble over the feta and serve with creme fraiche alongside.