Roast lamb with mustard and herbs

Ingredients

• 4 medium (800g) potatoes, peeled
• 1 medium (150g) brown onion
• 1 1/2 cup (375ml) chicken stock
• 1 1/2 tablespoon dijon mustard
• 3 clove garlic, crushed
• 2 anchovies, drained, chopped
• 2 teaspoon finely grated lemon rind
• 2 kilogram lamb leg
• 1/2 cup coarsely chopped fresh flat-leaf parsley
• 2 tablespoon coarsely chopped fresh oregano
• 1 medium (140g) lemon, cut into wedges