In a Dutch Oven, heat the olive oil over medium high heat until it just smokes. Add sausages and cook until browned all over, about 10 minutes. Transfer the sausages to a paper towel lined plate, drain all but approximately 1 tablespoon of fat.
Add the onion to the pot and cook until softened over medium heat, about 5 minutes. Add garlic and cook until fragrant, about 30 seconds. Add the broth and the bay leaf, scraping the bottom of the pot to pull up any browned bits. Bring to a boil.
Slice the sausage into 1/2 inch slices, and add to the pot. Add the tortellini and simmer until pasta is tender, about 10 to 12 minutes. Add in the spinach and cook until wilted, about 1 minute. Discard the bay leaf and season with salt and freshly ground black pepper to taste. Serve.