Add the olive oil to a medium pot over medium heat. When warm, add the garlic, onion, celery, and carrot. Stir to coat and cook for 6 minutes, or until just starting to soften.
Add 1 quart of the broth and raise the heat to high. When the broth starts to boil, turn down the heat to medium so it simmers.
Add the zucchini and pasta. Cook for about 8 minutes, stirring occasionally.
Stir in the peas. Add any of the optional flavorings as you like.
As the soup sits, the noodles will continue to absorb more of the broth. Add additional broth as you like to make it more or less brothy. (And save the broth to add for when you reheat leftovers.)
Season to taste with salt and pepper. Serve warm.
Notes
Store leftovers in an airtight container for up to 5 days in the fridge. Warm in a small pot or in a heat-safe bowl in the microwave, adding more broth if desired.
Make this easier by starting with pre-cut mirepoix from the produce aisle of your supermarket. Or make homemade mirepoix and stash it in the freezer.
Simmer Parmesan rind in the broth for extra flavor.
Gluten-free: Make the soup as directed and cook the gluten-free pasta separately according to package directions. Add to the soup. Or, you can add fully cooked rice.