In a large pot, heat 2 tablespoons of olive oil over medium heat. Once shimmering, add 1 pound of Italian sausage, breaking it up with a wooden spoon. Sauté until browned and cooked through, about 6–8 minutes.

Add 1 diced onion to the pot and stir, cooking until translucent, about 4–5 minutes. Mix in 3 minced garlic cloves, 1 teaspoon dried oregano, 1 teaspoon dried thyme, and a pinch of crushed red pepper flakes. Cook for another 1–2 minutes.

Add 6 cups of low-sodium chicken broth and one 14.5-ounce can of diced tomatoes (with juices) to the pot. Stir thoroughly and bring to a gentle boil, letting it combine for about 5 minutes.

Stir in 9 ounces of fresh cheese tortellini and lower the heat to a simmer. Cook according to package instructions, typically 3–5 minutes.

Once the tortellini are cooked, add 4 cups of fresh spinach to the pot, stirring gently until wilted, about 1–2 minutes.

Taste the soup and season with salt and pepper as desired. Serve hot, garnished with grated Parmesan cheese if you like.