Butterflied Honey Dijon Roast Chicken with Gravy

• 1 whole chicken
• ¹⁄₄ cup olive oil
• ¹⁄₄ cup lemon juice
• 1 tbsp heaping dijon mustard
• 1 tbsp honey
• 3 fresh thyme sprigs
• 1 tsp fresh rosemary
• ¹⁄₂ tsp ground coriander
• 1 tsp smoked paprika
• 8 garlic cloves
• ¹⁄₂ tsp Black pepper
• 1 tsp Salt
• 4 tbsp butter
• 3 celery sticks
• 2 carrot (medium)
• 1 yellow onion (large)
• 1 tbsp oil
• 1 garlic bulb
• Salt (to taste)

Gravy

• 3 tbsp 3-4 flour
• 2 cups chicken broth
• Salt, black pepper, white pepper (to taste)