Heat the olive oil in a large soup pot over medium heat. Add the onion and cook, stirring, until golden, 6-7 minutes. Add the garlic and cook, stirring, 1 minute. Add the carrot and zucchini and cook until softened, 3-4 minutes. Add the tomatoes and broth, bring to a boil, reduce the heat and simmer until the vegetables are tender, 15 minutes. Stir in the tortellini and cook until tender, an additional 5 minutes. Stir in the pesto, cheese, salt, and pepper and cook, stirring, 2-3 more minutes. Season with more salt and pepper to taste. Divide among bowls, swirl in more pesto, and garnish with cheese and basil.