Step 1

Heat the oil in a medium (4 quart) pot over medium heat.

Step 2

Add scallions and tarragon or basil and cook, stirring occasionally until scallions are soften, 4 minutes.

Step 3

Add peas, stir for 1 minute. Add vegetable broth and bring mixture to a simmer and cook until peas are tender, 4 to 5 minutes.

Step 4

Remove soup from heat and, working batches, use a blender to puree the soup with the mint until smooth.

Step 5

Return the soup to a pot, stir in 2 tablespoons lemon juice and season with salt and pepper.

Step 6

Keep soup warm until ready to serve.

Step 7

Combine yogurt, lemon zest coriander and a pinch of salt.

Step 8

Dollop soup servings with 2 1/4 teaspoons yogurt mixture just before serving.