Heat a large saucepan over medium heat and add the olive oil or butter. Once shimmering or melted, add the diced onion and gently sweat for about 5-7 minutes, stirring occasionally until translucent and fragrant.
Add the fresh peas to the pan and cook for 2 minutes, just long enough to brighten their color and release their sweet aroma. If using frozen peas, rinse and thaw them beforehand.
Pour in the vegetable broth, then bring the mixture to a gentle simmer. Cover with a lid and cook for about 8-10 minutes until the peas are tender and the broth is infused with their sweetness.
While the soup simmers, roughly chop the mint leaves. Add them to the pot during the last 2 minutes of cooking to preserve their fresh, herbal aroma.
Remove the pot from heat. Use an immersion blender directly in the pan to blend the soup until smooth and velvety, about 1-2 minutes. Alternatively, transfer to a regular blender and puree carefully.
If desired, pass the pureed soup through a fine-mesh sieve to ensure extra silkiness. Return the smooth soup to the heat if needed.
Stir in the fresh cream or coconut milk, warming through for about 2 minutes. Taste and season with salt and pepper, adjusting to your preference.
Serve the soup hot, garnished with a drizzle of olive oil or a small sprig of mint for a fresh finishing touch. Enjoy the bright green, silky smooth bowl of summer in every spoonful.
