Warm 1 tablespoon of olive oil in a deep, nonstick skillet (12-inch) over medium heat until it begins to shimmer. Add the ground beef and ½ teaspoon of the salt, cooking and crumbling the meat until fully browned. Remove the skillet from the heat, drain excess fat, and set the cooked beef aside on a plate.
Return the pan to the burner and pour in the remaining tablespoon of oil. Add the sliced onion along with ¼ teaspoon salt, sautéing for around 5 minutes until tender and lightly caramelized.
Incorporate the bell peppers, mushrooms, and minced garlic into the pan. Cook for 3–4 minutes, stirring frequently, until the vegetables begin to soften and the garlic is aromatic.
Return the reserved beef to the skillet. Sprinkle in the Italian seasoning, garlic pepper, and the final ¼ teaspoon of salt. Stir everything together and let cook for another minute or two.
Mix the uncooked rotini into the skillet. Pour in the beef broth and raise the heat to bring it to a boil. Once boiling, reduce the heat to low, cover, and simmer for 15 minutes, stirring occasionally, until the pasta is al dente and most of the liquid has absorbed.
Add the shredded pepper jack to the pasta mixture and stir until well combined. Lay the provolone slices over the top in a circular pattern. Cover the skillet again and heat just until the cheese has melted completely. Serve immediately.