Melt ghee over medium-high heat in a saucepan. Add onion and garlic and cook 3 to 5 minutes. Add broccoli florets and cook another 3 to 5 minutes, stirring occasionally. Sprinkle with cumin, thyme and nutmeg; season to taste. Add vegetable stock, mix well and bring to a simmer. Lower heat to medium and cook 30 to 35 minutes. Pulse broccoli with an immersion blender until smooth. Alternatively, you can transfer soup to blender. Pour in coconut milk, and give another pulse until combined well. Adjust seasoning and heat another 3 to 5 minutes.