Roast chicken and cabbage with soy butter

Ingrediënten

• 2 hispi cabbages, quartered (1kg)
• 2 heads of garlic, top 1cm removed
• 2 bunches of spring onions, cut into thirds (160g)
• 325ml chicken stock
• 70g ginger, peeled and cut into matchsticks
• 1 whole chicken, spatchcocked (1.7kg)
• 2 tbsp olive oil
• 100g unsalted butter, cut into small cubes
• 2 tbsp soy sauce
• Fine sea salt and white pepper