Heat the baking tray in the oven while you are pre-heating the oven to 425°F .
Peel the sweet potatoes and cut them into similar sized pieces about ¼″ wide and ¼″ thick so the fries will bake evenly.
Toss the unbaked potatoes in an olive oil, ancho chile and salt mixture before you place them on the baking tray.
Spray the baking tray with olive oil just before you lay the potatoes on the heated tray with space in between them and bake. Spacing them will allow them to become golden and crispy. Cook for 20-25 minutes, turning the potatoes once during to cook evenly. Serve with ancho chipotle mayo for some extra spice.