Remove the tails from the shrimp and cut the andouille into even bite-sized rounds. Keep the shrimp separate so it can be added near the end and stay tender.

Heat the oil in a non-stick skillet, then brown the sausage until the cut sides are golden and lightly crisped. Transfer the sausage out of the skillet once it has released flavorful drippings.

Cook the onion in the same skillet for 2-3 minutes, then add the bell peppers and celery and cook until tender. The onion should smell sweet and look translucent before the remaining vegetables soften.

Stir in the garlic, cauliflower rice, salt, pepper, and Cajun seasoning, then simmer for several minutes. Scrape the browned bits from the skillet bottom as the seasonings bloom and coat the cauliflower.

Add the diced tomatoes, chicken broth, and shrimp, then simmer until the liquid reduces and the mixture thickens. The shrimp are ready when they are completely pink and opaque and the sauce clings to the ingredients.

Return the sausage to the skillet and simmer for a further minute, then remove the pan from the heat and season to taste with extra salt and pepper. Serve right away while the cauliflower rice is tender and the shrimp are still juicy.