Saute. Heat olive oil in a large pot or Dutch oven over medium heat. Add the diced onion and cook for 3 to 4 minutes until softened. Add garlic and stir for 30 seconds until fragrant.

Simmer. Pour in the chicken broth and bring to a gentle boil. Add the tortellini and cook according to package directions, usually 3 to 5 minutes for fresh or 5 to 7 for frozen.

Stir. Reduce heat to low. Add the pesto and heavy cream, stirring until the broth turns creamy and green. Let it warm through for 1 to 2 minutes (don't let it boil after adding cream).

Wilt. Toss in the baby spinach and halved cherry tomatoes. Stir gently until the spinach wilts down, about 1 minute.

Serve. Ladle into bowls and top with parmesan shavings, a drizzle of pesto, and crusty bread on the side.