Heat the olive oil in a stock pot over medium heat. Add in the onions, squash, celery and carrots with a big pinch of salt and pepper. Cook for 6 to 8 minutes, stirring often, until the vegetables are slightly softened. Stir in the garlic cloves and dried thyme, cooking for another minute or so.

Add 4 cups of the stock stock and the parmesan rind. Bring the mixture to a boil. Reduce to a simmer and add the pasta. Cook for 8 minutes, stirring occasionally, or until the pasta is tender. Taste and season with more salt and pepper as needed. You can add in the additional cup of stock here if you want a brothier soup.

To serve, chop up baby spinach and place it in the bottom of a bowl. Ladle the soup on top. Serve with lemon wedges for spritzing and parmesan cheese for sprinkling.