Preheat the oven to 450 degrees.
Add the peeled and diced sweet potatoes to a glass casserole dish.
Sprinkle the sweet potatoes with the garlic powder, onion powder, thyme, pepper, salt, and paprika.
Drizzle on enough olive oil to coat the sweet potatoes (up to 1/3 cup).
Toss the mixture with your hands to combine the sweet potatoes with the oil and spices.
Roast the sweet potatoes at 450 degrees for 55-65 minutes, stirring every 15-20 minutes, until crispy on the edges. Each time you stir the sweet potatoes, use a hard plastic spatula to scrape up any edges that have stuck to the pan. This is what gives them those crispy edges! Watch the sweet potatoes closely towards the end of cook time to avoid burning them.
Once the sweet potatoes have about 15 minutes left to cook, add the minced garlic and diced onion to a skillet with 1 teaspoon of olive oil.
Cook the garlic and onion for 10-15 minutes on medium heat, stirring often, until soft and caramelized.
Once the sweet potatoes have finished cooking, remove them from the oven and stir in the garlic and onion mixture before serving.