BEFORE YOU BEGIN
If you'd prefer to substitute small pasta such as tubetti, ditali, elbow macaroni, or small shells for the ditalini, do so by weight, not by volume. We prefer frozen petite peas (also labeled as petit pois or baby sweet peas) in this recipe because they are sweeter and less starchy than fresh peas or regular frozen peas, but you can substitute regular frozen peas, if desired. Do not defrost the peas before using them. For a vegetarian version, omit the pancetta, substitute vegetable broth for the chicken broth, and add an extra 2 tablespoons of grated cheese. Pecorino Romano adds a welcome sharpness; we do not recommend substituting Parmesan in this recipe.