Heat oil in a saucepan over medium heat. Add garlic and onion and cook until translucent. Add peas, vegetable broth, and salt to the saucepan and bring to a boil. Reduce heat and simmer for 10 minutes.
Add coconut milk (reserve a quarter of it for drizzling) and mint leaves to soup mixture. Using an immersion blender, blitz until smooth.
Transfer to serving dishes, drizzle with reserved coconut milk, and garnish with mint leaves.