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, stirring frequently to prevent burning.

Increase the heat to medium-high and add the ground beef to the skillet. Cook until browned, breaking it apart with a spatula, about 5-7 minutes.

Stir in the halved Brussels sprouts, salt, black pepper, smoked paprika, and red pepper flakes (if using). Cook for another 5-7 minutes, stirring occasionally, until the Brussels sprouts are tender and slightly caramelized.

Pour in the soy sauce, balsamic vinegar, and beef broth. Stir well to combine and let it simmer for an additional 3-4 minutes until the liquid reduces slightly.

Remove from heat and garnish with chopped fresh parsley before serving.