Finely dice the onion into 1/4-inch pieces, chop the carrots and celery into bite-sized pieces, and mince the garlic cloves. Cube the red potatoes into 1/2-inch pieces and set aside in a bowl. In a large pot over medium-high heat, brown the sausage for 10-12 minutes, breaking it into small crumbles as it cooks. Once cooked through, transfer the sausage to a paper towel-lined plate to drain, leaving about 1 tablespoon of the rendered fat in the pot. I like using Italian sausage here because it has enough fat to flavor the broth without being greasy.

Add 2 tablespoons butter to the sausage fat in the pot and melt over medium heat. Add the diced onions, carrots, and celery, stirring occasionally and cooking for 5 minutes until the vegetables begin to soften and release their aromatics. Add the minced garlic and cook for 1 minute more, stirring constantly to prevent burning. Sprinkle the flour over the vegetables and stir constantly for 2 minutes to cook out the raw flour taste and create a light roux. This roux will help thicken the soup and give it a velvety texture.

Slowly pour the chicken broth into the pot while stirring to prevent lumps from forming in the roux. Add the heavy cream, soy sauce, and hot sauce, stirring until well combined. Add all the dried seasonings: basil, parsley, oregano, mustard powder, pepper, and smoked paprika. Stir thoroughly to dissolve the seasonings and distribute them evenly throughout the liquid. I find adding soy sauce gives the soup an extra savory depth that makes people ask what the secret ingredient is!

Increase heat to bring the broth to a gentle boil, then immediately reduce heat to medium-low and maintain a steady simmer. Add the cubed potatoes from Step 1, stirring gently to distribute them evenly throughout the pot. Simmer for 20-25 minutes until the potatoes are completely tender when pierced with a fork. The potatoes should break apart easily but still hold their shape. While the potatoes cook, shred the cheddar cheese from a block using a box grater or microplane if you haven't already—freshly shredded cheese melts much more smoothly than pre-shredded varieties.

Once the potatoes are tender, stir in the cooked sausage from Step 1, heating it through for about 1-2 minutes. Remove the pot from heat and gradually add the freshly shredded cheese, stirring gently and constantly until it's completely melted and the soup is smooth and creamy. Taste and adjust seasonings if needed. Ladle the soup into bowls and serve hot. I recommend removing the pot from heat before adding cheese so it melts evenly without becoming stringy or separating.