Step 1

Heat a medium-sized saucepan over medium heat. Add the olive oil, celery, carrot, and shallots and cook, stirring often for about 5 minutes, or until softened.

Step 2

Add the sprigs of thyme, salt, Parmesan rind, chicken broth, and water. Bring to a simmer and cook for 10 minutes.

Step 3

Add the pasta and stir with a wooden spoon to prevent sticking to the pan. Return to a simmer and continue to cook for 8 to 10 minutes more, or until the pasta is cooked and the liquid is slightly thickened.

Step 4

Remove the thyme sprigs and Parmesan rind. Stir in the peas. Ladle the soup into bowls and top with grated cheese and lemon zest, if desired.