To large pot of boiling water, add peas and green onions. Reduce heat and simmer for 10 minutes. Drain, reserving 1 to 2 cups of the cooking liquid. Return vegetables to the pot and add salt and lime juice. Using an immersion blender, purée the mixture; the soup should have the consistency of thick cream. Blend in some of the reserved cooking liquid if it seems too thick and closer to a pesto.

In small frying pan, heat oil over medium-high heat. Add pancetta and fry until brown and edges are crispy, about 3 minutes. Transfer to a paper-towel-lined plate. (Or, for a vegetarian version, toast pine nuts over low heat until just browned. Be warned: They burn easily!)

To serve, divide soup among bowls and top each with 1 tbsp yogurt. Add spoonful of either pancetta or pine nuts and sprinkle with mint and pepper to taste.