Peel and chop the potatoes, carrots, and leeks.
Heat olive oil in a pan and add the ajwain (carom) seeds.
Add the chopped vegetables and garlic powder, and sauté for 3-4 minutes.
Transfer the cooked vegetables to a blender and blend until smooth.
Transfer the pureed soup back to the pan.
Add butter and stir until melted.
Add hot water to adjust the consistency as desired.
Simmer the soup for a few minutes.
Serve the soup hot, with a dollop of double cream on top.
