1.Preheat oven to 200C. Combine stock, lentils, bay leaf and 300ml water in a saucepan, bring to the boil over medium-high heat, skim scum, reduce heat to medium, simmer until lentils ar just tender and most stock is absorbed (15-2 minutes), season to taste, keep warm.
3.Meanwhile, process age, mustard, garlic, vinegar and 1½ tbsp oil in a small food processor to a smooth paste, season to taste and brush thickly over both sides of each cutlet. Heat remaining oil in a large ovenproof frying pan over medium-high heat, add cutlets and cook, turning once, until golden (2-3 minutes), transfer to oven until just cooked through (4-5 minutes). Serve hot with lentils and red wine cabbage.