- In a large skillet, heat the olive oil over medium heat. Add the diced onion and cook for about 3-4 minutes until softened. 
- Add the minced garlic and cook for an additional 1 minute until fragrant. 
- Increase the heat to medium-high and add the ground beef. Cook until browned, breaking it apart with a spatula, about 5-7 minutes. Drain excess fat if necessary. 
- Stir in the Brussels sprouts, salt, black pepper, smoked paprika, soy sauce, balsamic vinegar, and beef broth. 
- Cover the skillet and reduce the heat to medium. Cook for 8-10 minutes, stirring occasionally, until the Brussels sprouts are tender. 
- If using, sprinkle the red pepper flakes over the mixture for added heat. Stir well and cook for an additional 1-2 minutes. 
- Serve hot, garnished with fresh herbs if desired.