In a dutch oven or soup pot, add the sliced mushrooms and a tiny drizzle of olive oil. Cook over medium heat until soft. DO NOT caramelize or brown them. Do NOT add salt or pepper or any seasonings yet. Before you move to the next step, once the mushrooms are soft and slightly golden take a paper towel and quickly wipe the bottom of pot if the mushrooms left any brown liquid from sautéing. you don't have to remove the mushrooms, just a quick couple swishes in the pot.
Add the sliced onions and chopped garlic, to the pot with the mushrooms. Add another tbsp or so of olive oil and saute with the mushrooms until softened. Then, add the bulk Italian sausage and mix into the veggies with a wooden spoon while also breaking up the bulk sausage. Continue cooking at medium heat until you no longer see pink in the sausage.
Season the mixture with dried basil, oregano, mustard powder, red pepper flakes, hot sauce, and cayenne. Continue to sauté for an additional 2-3 minutes, ensuring the seasonings are evenly distributed.
Sprinkle the flour over the sausage and vegetable mixture. Stir constantly for 2-3 minutes, allowing the flour to cook and create a roux.
Pour in the chicken broth, water, and heavy cream and then stir. bring the mixture to a boil. Once boiling, reduce the heat to a simmer. Add the hunk of Pecorino romano cheese and a shake of hot sauce into the pot.
Let the soup simmer uncovered for 5-10 minutes, allowing the cheese to melt and the flavors to meld together.
Bring the pot of soup back up to a boil. Add the uncooked cheese-stuffed tortellini and the baby spinach. Boil for 3-5 minutes or until the tortellini is cooked and aldente.
To serve, garnish your creamy sausage and tortellini soup with grated Pecorino Romano cheese and fresh parsley. Enjoy your homemade, comforting bowl of soup!
