Chilled Carrot Soup With Lemon And Dill Yoghurt

Ingredients

• 1 1/2 kg carrots, coarsely chopped (about 12)
• 2 onions, coarsely chopped
• 1 garlic head, halved horizontally
• 60 ml olive oil (¼ cup)
• Finely grated rind and juice of 3 lemons and 1 orange
• 600 ml buttermilk
• 250 gm thick plain yoghurt
• 3 tbsp finely chopped dill, plus extra sprigs to serve
• 2 spring onions, thinly sliced
• To serve: pea shoots (optional)