Tarragon & mustard roasted free-range chicken

INGREDIENTS

• 1 large bunch tarragon , leaves chopped and stalks reserved
• 2 large onions , cut into large chunks
• 2 large carrots , cut into large chunks
• 3 sticks celery , roughly chopped
• 1 head fennel , roughly chopped
• 100ml olive oil , plus more for drizzling
• 1 garlic head, roughly chopped (skin and all)
• 2 x 1½kg free-range chicken
• 1 lemon , quartered
• 1 tbsp Dijon mustard , plus 1 extra tsp
• ½ bottle hearty red wine
• 500ml chicken or vegetable stock