To start, remove the casings from your Italian sausage if you're using links. Preheat your large soup pot over medium heat. Add the ground sausage to the pot and cook, breaking it apart with a wooden spoon or silicone spatula. Stir the sausage occasionally as it cooks, making sure to crumble it into small bits. It will take around 10-12 minutes for the sausage to cook all the way through, becoming nice and browned. Once fully cooked, remove the sausage from the pot and set it aside. Be sure to reserve about 1 tablespoon of the drippings for the next step. (If you don’t have enough drippings, you can simply use butter.)
Add the reserved sausage drippings to the pot, along with the butter, and heat over medium. Once the butter has melted, toss in the diced onion, carrots, and celery. Cook these vegetables for about 5 minutes, stirring occasionally, until they begin to soften and the onion turns translucent. Then, add the minced garlic and cook for an additional minute, stirring to release its fragrance
Next, sprinkle the flour over the softened vegetables and stir it in to coat the mixture. Let it cook for about 2 minutes, stirring frequently, to create a slight roux that will help thicken the soup later. Once the flour is fully incorporated, add the soy sauce, hot sauce (if using), and all your dried herbs—basil, parsley, oregano, mustard powder, and pepper. Stir the seasonings into the vegetables, allowing them to infuse the mixture with flavor.
Now that your base is ready, you’re ready to move on to the next step—bringing your sausage and vegetable mixture to life with the addition of broth and potatoes!