Preheat your oven to 425°F (220°C).
Wash and trim the Brussels sprouts, then cut them in half.
In a mixing bowl, toss the Brussels sprouts with olive oil, salt, black pepper, and garlic powder until evenly coated.
Spread the Brussels sprouts on a baking sheet in a single layer.
Roast the Brussels sprouts in the preheated oven for 20-25 minutes, stirring halfway through, until they are crisp on the edges and tender inside.
While the Brussels sprouts are roasting, heat a skillet over medium-high heat.
Add the lean ground beef to the skillet, breaking it up into small pieces as it cooks.
Cook the beef for 6-8 minutes or until it's fully browned and cooked through. Season lightly with salt and pepper if desired.
Once both components are ready, plate the roasted Brussels sprouts and top with the cooked ground beef.
Serve immediately and enjoy your hearty, nutritious meal.