Heat olive oil in a large skillet or Dutch oven over medium-high heat. Add ground beef and cook, breaking it apart with a spoon, until browned and no pink remains, about 5-7 minutes. Drain any excess fat and set beef aside briefly if using the same skillet for vegetables to avoid overcrowding.

If you removed the beef, add a tiny bit more olive oil if needed. Add chopped onion to the skillet and cook until softened, about 3-4 minutes. Stir in minced garlic and cook for another minute until fragrant.

Add diced red bell pepper, yellow bell pepper, and zucchini to the skillet. Sauté for 3-5 minutes, allowing vegetables to slightly soften but still retain some crunch.

Return the cooked ground beef to the skillet (if removed). Stir in the undrained diced tomatoes, low-sodium beef broth, rinsed uncooked quinoa, Italian seasoning, smoked paprika, salt, and black pepper. Mix everything well.

Bring the mixture to a boil. Once boiling, reduce the heat to low, cover the skillet, and simmer for 15-20 minutes, or until the quinoa is fully cooked and has absorbed most of the liquid. Fluff the quinoa with a fork.

Remove from heat and let stand, covered, for 5 minutes. Garnish generously with fresh chopped parsley before serving.