Garlic Herb Slow Cooker Turkey Breast

Bahan-bahan (8 porsi)

• 2.5 - 3 kg / 5-6 lb single turkey breast (, skin on, bone in (Note 1), NOT BRINED)
• 1/2 tsp salt
• Black pepper
• 1 brown onion (, halved)
• 1 head of garlic (, halved horizontally)
• 3 sprigs rosemary, 8 sprigs thyme (optional)
• Oil (, for drizzling (for skin))
• 150 g / 10 tbsp unsalted butter (, softened)
• 1 1/2 tsp salt
• 1/2 tsp black pepper
• 4 large garlic cloves (, minced)
• 1 tbsp EACH finely chopped fresh sage, rosemary leaves, thyme leaves and parsley (, fresh)
• Chicken broth/stock, for topping up ((if required))
• 1/3 cup / 50g flour
• 1/2 tsp + dark soy sauce ((or gravy colouring) (Note 3))