Slow Cooked Cauliflower with Yoghurt - River Cottage

Ingredients

• 150g butter
• 1 onion, diced
• 1 clove garlic, chopped
• 1 tsp cumin seeds, crushed
• 1 tsp coriander seeds, crushed
• 1 tsp mild chilli flakes
• 1 cauliflower, stalk and tough outer leaves removed
• 1 handful coriander leaves
• 1 egg yolk
• ½ tsp cornflour
• 500ml Greek yoghurt
• Unblanched almonds, chopped, to serve