In a large pan set over medium-high heat, cook the Italian sausage in olive oil until golden, crumbling it as it cooks. Using a slotted spoon, transfer the cooked sausage to a plate and set aside.
In the same pan, sauté the onions for 4 to 5 minutes, or until tender and translucent, stirring occasionally. Add the garlic and sauté for an additional 1 to 2 minutes, or until fragrant, stirring occasionally. Incorporate the flour, ensuring it evenly coats the vegetables, and continue to cook for an additional minute, stirring occasionally.
Gradually add the chicken broth and stir to combine. Continue to cook until liquid starts to boil. Reduce heat to medium-low and let simmer 5 minutes.
Add the cooked sausage, tortellini, kale, and cream and continue to simmer for 4 to 5 minutes, or until the tortellini is al dente.
Taste and season with salt and pepper.
Garnish with fresh herbs and spicy olive oil if desired.