If you prepare chips in the oven instead of in the deep fryer, you save calories. Preheat oven to 200° C. Line baking tray with baking paper. Mix deep-frozen French fries with oil. Distribute them on the baking tray so that they do not lie on top of each other. Bake the French fries on the middle shelf for 25 to 30 minutes until crispy, depending on their thickness. In between, open the oven door carefully to let the water steam out. Turn the French fries over with the roasting turner. If the fries do not brown and remain soft, you can leave them in the oven for longer, but they will usually be too dry. It is best to try a different brand next time, as there are differences in quality.