Cook the noodles. Bring broth to a boil. Cook pasta according to package directions until just al dente. Reserve ½–1 cup cooking liquid, then drain.
Cook sausage. While pasta cooks, brown sausage in a large skillet over medium-high heat, breaking it into small pieces.
Put it all together. Add butter to the sausage, then stir in onion powder, garlic powder, Italian seasoning, salt, and pepper. Cook 1 minute. Add diced tomatoes and stir to combine. Add drained pasta and about ¼ cup reserved cooking liquid. Toss to coat.
Add Spinach. Bring to a gentle simmer. Add spinach one handful at a time, ripping it into smaller pieces as you add it, stirring until wilted before adding more. Add more reserved cooking liquid as needed, a little at a time, until everything comes together (no excess liquid).
Finish. Remove from heat and serve hot. Add Parmesan, Red Chili Flakes, or Parsley for Garnish.
