Melt butter in a large frying pan over medium heat. Add onion and sauté until soft (5-6 minutes). Add breadcrumbs, almonds, herbs and ground cinnamon, stir to combine and season to taste. Remove from heat and set aside to cool.
Preheat oven to 150C. Place breasts skin-side down on a work surface and spread over cooled stuffing evenly. Starting at the longest sides roll up each breast and tie securely at 5cm intervals with kitchen string.
Heat olive oil in a large heavy-based casserole over high heat. Add one lamb breast and cook, turning frequently until golden brown (5-6 minutes). Remove and repeat with remaining lamb. Return lamb to casserole with chicken stock and spices, bring to a simmer, cover, transfer to oven and cook until lamb is tender (2½ -3 hours).
Meanwhile, for sautéed red cabbage, heat butter over medium heat until just foaming. Add cabbage and cook, stirring occasionally, until wilted and tender (8-10 minutes). Season to taste.
Remove string from lamb, thickly slice and serve immediately with sautéed red cabbage.
Note Whole allspice, also known as pimento berries, are available from select delicatessens and online from Herbie’s Spices.