Preheat air fryer by running it at 400°F (205°C) for 5 minutes.
Place leftover French fries in air fryer basket and mix with a little bit of oil, or spritz with cooking spray. Season as desired.
2 handfuls leftover French fries, olive oil
Air fry 4-6 minutes at 400°F (205°C), shaking the fries once halfway. Check to make sure they are heated through, then serve!
Notes
This recipe has been tested with the following air fryer models (affiliate links): Philips HD9252/90 Air Fryer, Ninja DZ401 DualZone XL Air Fryer and Cosori Pro II. . Cooking time can vary with your specific model.Add seasonings before reheating. Add a bit of oil first to ensure the seasonings stick to the fries, then season as you like before air frying. I like adding a bit of salt or some spices.Don't overcrowd your air fryer basket. You can have multiple layers, but don't fill it all the way upAdjust cook time depending on how much you're reheating. 4 minutes is generally enough for a small amount of fries, for larger quantities you might need 6 minutes.Use high temperature for the crispiest results. The fries don't need to "cook", they just need to heat back up again and regain a bit of crisp. For this reason I like to cook them at a high temperature (400°F or 205°C). Just keep an eye on them so they don't burn!