Courgette, Parmigiano Reggiano and crème fraîche soup

Ingredients

• 1 onion, chopped
• 2 cloves garlic, chopped
• 1 tbsp olive oil
• 1 kg courgettes, chopped
• 1.5 handfuls basil leaves
• 650 ml vegetable stock
• 2 inch piece Parmigiano Reggiano rind
• Zest of 1 lemon
• 100 g grated Parmigiano Reggiano
• 4 tbsp crème fraîche
• 25 g shaved Parmigiano Reggiano
• Salt and pepper