Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Peel and dice the sweet potato into 1/2-inch cubes, then toss them on the baking sheet with olive oil, half of the salt, and half of the pepper.
Roast the sweet potatoes for 20-25 minutes, flipping halfway through, until they are tender and slightly caramelized.
While the potatoes roast, heat a non-stick skillet over medium-high heat and add the ground beef.
Season the beef with garlic powder, onion powder, and the remaining salt and pepper, breaking it into small crumbles as it cooks.
Cook the beef for 7-8 minutes until fully browned and no longer pink, then remove from heat.
Assemble the bowls by placing a bed of baby spinach at the bottom, followed by the roasted sweet potatoes and the cooked ground beef.
Top the bowls with diced red onion, halved cherry tomatoes, and sliced avocado.
Drizzle with yellow mustard and serve immediately.