Preheat the oven to 400 degrees.
In a small bowl, mix all the spices together.
Rip off 4 sheets of aluminum foil, about 12 inches long each.
Slice and dice the sweet potato into smaller pieces. Divide the diced sweet potato into 4 sections.
Take one of the aluminum foil sheets, and put one section of the sweet potatoes onto the middle of it. Top the sweet potatoes with 1 tsp of olive oil and 1/4 of the spices. Fold up the sides of the aluminum foil and crumble the sides down on top, creating a closed pocket. (If my directions are confusing, the photos above could help).
Repeat this step with the other 3 sections of the sweet potatoes, putting 1 tsp of olive oil and 1/4 of the spices on the potatoes.
Put all 4 aluminum foil packets onto a cookie sheet and put them into the oven for 30 minutes. You'll know the potatoes are done when you can push a knife easily through the cubes of sweet potatoes.
Cook for 30 minutes. 30 minutes makes the sweet potatoes very soft, but if you want them to be harder, start checking them at around 25 minutes.