Wash the sweet potatoes very well in water and slice the sweet potatoes in round slices (you may peel the sweet potatoes if you wish). Make sure to slice them evenly and keep the slices slightly thick like ½ inch thickness.
Transfer the sliced sweet potatoes to a bowl and add the salt, oil, garlic powder and black pepper powder also to the bowl. Toss very well with your hands so the spices will blend well with the sliced sweet potatoes.
Preheat the oven to 400 degree Fahrenheit.
Layer a baking sheet with foil (greased with little oil) or non slip baking mat and place the sweet potato slices in a single layer (in case there is more slices you can always do in a second batch, but make sure to layer them in a single layer so as not to overcrowd the baking sheet).
Bake in the preheated oven for about 35 to 40 minutes or until the top begins to lightly brown.
To make it more crunchy, crispy and delicious, increase the oven temperature to 450 degree Fahrenheit (flip the slices very carefully if you can) and bake for another 6 to 7 minutes. Always watch them during the final minutes of baking to avoid burning of the sweet potatoes. Once they are baked enough to your liking, immediately transfer from the hot oven, allow them to cool down slightly and enjoy!