Heat oil in a large pot over medium heat and sauté diced onion until translucent, about 5 minutes.
Add minced garlic and chopped ginger, cooking for 1 minute until fragrant.
Add diced beets and a pinch of salt, stirring to combine.
Pour in vegetable stock and bring to a simmer. Cook until beets are tender, about 30 minutes.
Using an immersion blender or regular blender, blend soup until completely smooth.
Stir in coconut milk if using and adjust salt to taste.
Serve hot with optional garnishes of lemon zest, toasted pistachios, and fresh parsley.