Nature's Fresh chuck beef pot roast - Nature's Fresh

Ingredients

• 1.4kg piece Nature’s Fresh chuck beef
• sea salt flakes and freshly-ground black pepper
• 2 Tbsp vegetable oil
• 6 sticks celery, including leaves
• 16 small potatoes
• 4 carrots, chopped
• 2 red onions, chopped
• 6 cloves garlic, chopped
• 2 tsp fennel seeds
• 1 tsp celery seeds
• 1 tsp yellow mustard seeds
• 2 sprigs rosemary leaves
• 4 bay leaves
• 750ml white wine
• 1L chicken stock
• 1 Tbsp Dijon mustard
• 2 Tbsp unsalted butter
• 2 Tbsp plain flour
• 1 bunch tarragon, very finely chopped