Halve, slice, wash the leeks well and drain. Heat the oil in a skillet over medium heat. Add the leeks and cook until softened but not brown, about 5 minutes. Add the peas and continue cooking until the peas are thawed and bright green, about 3 minutes. Transfer the peas and leeks to a blender along with the sour cream, salt, parsley, and lemon. Blend on low until smooth. Garnish with the scallions.
Recipe courtesy of Dave Lieberman