Preheat your oven to 425°F.
In a bowl, gently mix the lean ground beef with a pinch of salt and pepper. Form into a patty roughly 5 ounces in weight.
Place the beef patty on a lightly oiled baking sheet or cast-iron skillet. Bake in the preheated oven for about 12-15 minutes, or until cooked through. Optionally, you can finish the patty on a hot skillet for a minute on each side for a crispier exterior.
Meanwhile, peel (if desired) and cut the sweet potato into 1/2-inch thick rounds or wedges. Toss with half of the olive oil, salt, and pepper. Spread them out on a separate baking sheet.
Roast the sweet potatoes in the oven for about 20-25 minutes, turning halfway through, until they are crispy on the edges and tender inside.
Trim the ends off the green beans, then toss them with the remaining olive oil, salt, and pepper. Spread on a baking sheet and roast for 12-15 minutes along with the beef or after the sweet potatoes are done, until they are tender but still retain a bright green color.
Plate your beef burger along with a serving of roasted sweet potatoes and green beans. Enjoy your balanced and delicious meal!