Step 1

Remove rind and trim fat from pork. Cut pork into six pieces, toss in flour; shake away excess. Heat oil in a casserole dish over high heat; cook pork, in batches, for 10 minutes or until browned lightly. Remove from dish.

Step 2

Cook leek, celery and fennel in same dish, stirring, over medium heat for 8 minutes or until softened. Add garlic, thyme and chilli; cook, stirring, 1 minute or until fragrant. Add stock and water; bring to the boil. Return pork to pan; stir to cover with liquid. Reduce heat to very low; simmer, covered, for 2 hours or until tender, stirring occasionally.

Step 3

Meanwhile, make gnocchi: Place whole kumara in a medium saucepan; cover with cold water. Cover; bring to the boil. Reduce heat; simmer, partially covered, for 45 minutes or until tender. Drain. Cool slightly; peel.

Step 4

Mash kumara in a large bowl until smooth. Cool to room temperature. Stir in cheese and egg yolks; season. Add enough of the flour to mix to a soft, slightly sticky dough.

Step 5

Divide mixture into six portions; roll each portion on a floured surface into a 2cm thick log. Using a floured knife, cut logs into 2cm lengths. Place gnocchi on a large plastic-wrap-lined tray in a single layer. Cover; refrigerate until required.

Step 6

Remove pork from pan; shred into smaller chunks. Return pork to pan with olives and juice. Season to taste. Cover; keep warm over low heat.

Step 7

Cook gnocchi, in batches, in a large saucepan of boiling salted water for 2 minutes or until gnocchi float to the surface. Remove gnocchi with a slotted spoon; drain on paper towel.

Step 8

Serve gnocchi topped with ragu, sprinkled with reserved fennel fronds and extra thyme leaves, if you like.