First of all, you have to preheat the oven to around 450 degrees Fahrenheit. Depending on your personal taste, you can preheat the oven to 500 degrees Fahrenheit to make your potatoes a little crispier.
Take the peeler and peel the sweet potatoes. You have to cut the potatoes into halves (lengthwise). If they are too long after cutting, just cut them in half crosswise. After that, you have to cut them into wedges. You can now slice the peeled potatoes with a knife.
Now, take a large bowl and add some oil into it. Put all the potatoes into the bowl and mix them well. Add some salt, spices and sugar in the bowl and mix all the ingredients well with your hands.
Take the baking sheet and place each slice of sweet potatoes on it. It will be better if you spray some oil on the sheet before placing the potatoes, otherwise they may stick to the sheet.
Place the baking sheet in the oven and bake the potatoes for around 25 to 30 minutes. It is extremely important for you to turn the side of the potatoes slices after 15 minutes so that they are baked well from both the sides. Keep your eyes on the potatoes while they are in the oven and take them out when they are brown.
Before serving, let the potatoes cool down for around 5 minutes. Serve it with tomato ketchup or any other sauce.