Generously salt a pot of water and bring to a boil. If using fresh peas, add them for 1 minute, then snap peas for 2 minutes. If using frozen, only cook the snap peas at this point. Plunge the cooked peas into an ice bath to set the color and stop the cooking. It is important, especially with fresh peas, to maintain a nice crispness and vivid color. Cook the pancetta until crisp, about 10 minutes. Transfer to paper towel with a slotted spoon, but leave the drippings in skillet. Add flour to skillet and whisk to create a roux. Whisk in broth and cream and reduce until desired thickness, about 5 minutes. Add chicken broth as necessary to maintain a nice thick creamy consistency. Drain peas and add to the skillet (if using frozen, this is the point to add them). Heat through, stirring frequently, for about 5 minutes. Finish with lemon juice, salt, and pepper to taste. Top with the pancetta to serve. You can easily vary the proportions of peas to sugar snap peas or add sliced on whole snow peas (they only need to cook about 30 seconds). Play around with edamame, zip peas, etc. to vary the dish depending on what is fresh.