First, Cook The Sausage. Warm butter or oil in a large skillet over medium heat. Add sliced sausage and cook 8-10 minutes, or until browned and caramelized to your desired preference. Remove sausage from pan and set aside on a large clean plate/bowl.
Cook Peppers. Add diced bell peppers to the same skillet and cook 4-5 minutes, or until crisp-tender. (Cook 1-2 minutes longer if you don't want any bite at all.)
Add The Rest Of The Veggies. Add sliced green onions, garlic, and spinach to the peppers. Cook 1-2 minutes longer on medium heat, until spinach is wilted and the garlic is fragrant. Remove vegetables and set aside.
Build Flavor. Add tomato paste, broth, 1/2 tsp. Cajun seasoning and the salt to the pan and cook, whisking or stirring until the mixture is smooth. Cook the mixture 3-4 minutes, or until slightly thickened and smooth. Taste and add additional salt or Cajun seasoning, to taste. (You want it to be a bit strong-tasting, since the rice and veggies will dilute the flavor a bit.)
Assemble The Dish. Return cooked sausage and vegetables to the pan and add the cooked rice. Stir to coat with the sauce. Cook just 1-2 minutes longer to encourage the rice to absorb some of the liquid and allow the flavors to meld. Taste and add salt or pepper, to your liking. Garnish with cilantro or parsley & feel free to add black pepper or hot sauce, to taste.
Serve & Store. Enjoy right away. Store leftovers in an airtight container in the fridge 2-3 days.