Preheat the oven to 425°F (220°C). Peel the sweet potatoes, cut them lengthwise, divide each section into even portions, and cube them into similarly sized pieces so they cook at the same rate.
Place the sweet potato cubes in a large bowl. Pour in the olive oil and toss well so every piece is lightly coated.
Add the garlic powder, onion powder, paprika, brown sugar, cinnamon, salt, and black pepper. Mix thoroughly until the seasoning blend is evenly distributed over all of the sweet potato cubes.
Lightly grease a baking pan and transfer the seasoned sweet potatoes to it. Arrange them in a single layer with a little space between the pieces to encourage proper roasting and caramelization.
Roast for 30 to 35 minutes, turning the cubes with a spatula every 10 minutes to help them brown evenly and prevent scorching.
Test for doneness by inserting a toothpick into one of the larger cubes. When fully cooked, the sweet potatoes should be very soft in the center.
Remove the pan from the oven and let the sweet potatoes rest for a few minutes before serving. Serve warm as a side dish or on their own.