Spatchcocked roast chicken with orzo and roast vegetables

Ingredients

• 100g unsalted butter, softened
• 4 garlic cloves, crushed
• Grated zest and juice 1 lemon
• 2 tbsp finely chopped oregano leaves, plus extra for serving
• 2-2.2kg free-range chicken
• 1 large aubergine, cut into 4cm pieces
• 3 peppers, red or yellow, cut into 4cm pieces
• 2 large courgettes, cut into 4cm pieces
• 1 large red onion, cut into wedges
• 1 tbsp olive oil
• 300g orzo
• 3 tsp capers in brine, drained
• 3 tbsp chopped flatleaf parsley