Melt ghee in a large pot over medium-high heat. Add diced onion and stir. Cook for about 5 minutes.
While onion is cooking, wash and peel potato. Cut into large chunks.
Add potato to the pot and stir in 1 teaspoon sea salt and 4 cups of vegetable broth. Bring to a boil, then reduce heat and simmer for 10 minutes.
Remove woody ends of asparagus and cut into 2- to 3-inch pieces. Add to the pot and return to a boil, cooking for another 5 minutes. Remove from heat.
Add soup mixture to the jar of a blender, along with ½ cup canned coconut milk, the juice of half a lemon and ½ teaspoon each of sea salt and cracked black pepper.
Secure the lid on the blend, turn the power on and start pulsing or blending on low. Increase blending speed to high and blend for about 2 minutes, until soup is creamy and smooth.
Taste, adjust seasonings and serve.