Sauté Aromatics: Heat olive oil in a medium saucepan over medium heat. Add chopped onion and sauté until soft and translucent, about 3–4 minutes. Add minced garlic and cook for 30 seconds until fragrant.
Cook the Peas: Add peas and vegetable broth to the pan. Bring to a simmer and cook for 5–7 minutes until peas are tender.
Blend the Soup: Remove the soup from heat. Add fresh mint leaves and lemon juice (if using). Blend the mixture using an immersion blender or a countertop blender until smooth and creamy.
Season and Chill: Taste and adjust salt and pepper as needed. Transfer to a bowl, cover, and refrigerate for 1–2 hours until well chilled.
Serve: Pour into bowls. Garnish with a dollop of Greek yogurt, extra mint leaves, croutons, or a drizzle of olive oil. Serve cold for a refreshing starter.