Obtain the Duck Fat
You might already have some rendered duck fat in your refrigerator or freezer from the last time you roasted a whole duck or seared duck breasts. You will need enough to completely cover the potatoes as they are cooking, about 2 or 3 inches in the bottom of a pot. If you don’t have enough rendered duck fat on hand, supplement with our rendered duck fat.
Prep Your Potato
The russet potato is the ideal frying potato. Peel the skin for more refined frites, or scrub the skin well and leave it on for a rustic fry. Cut potatoes into sticks between 1/4-inch and 1/2-inch wide. Rinse the cut potatoes in cold water to remove any excess starch. If you have the time, soaking them in ice water for 30 minutes will yield even better results. Drain the potatoes before frying and pat them completely dry.
Learn the Correct Frying Technique
- The secret to the perfect french fry in any fat is the double-fry method. The first fry is to cook the potato through. The second fry at a higher temperature is to crisp them up.
- Melt the duck fat in a heavy-bottomed pot with high sides. Heat the fat to about 325 degrees F. A deep-frying/candy thermometer is really handy for getting an accurate reading.
- Cook the potato sticks in small batches to avoid dramatically dropping the temperature of the hot fat. After about 5 to 7 minutes, test the doneness by poking a fry with a knife. The knife should slide in and out with no resistance.
- If the potatoes are cooked through, remove them from the pot with a slotted spoon, spider skimmer, or tongs and drain on a sheet tray covered in paper towels. After all of the batches are cooked and cooled, raise the heat under the pot and bring the melted duck fat to 350 degrees F.
- Return the fries to the pot, in batches again, for only about 1 minute. Drain on fresh paper towels.
- Sprinkle them right away with your choice of sea salt, black pepper, paprika, parmesan cheese, fresh herbs, or whatever seasonings you like. Doing this step while the fries are still hot will help the seasonings to stick.
Consider Dipping Sauces
Your duck-fat French fries will be perfect by themselves. However, you can take them one step further by serving with a dipping sauce. Try serving them with mayonnaise mixed with fresh herbs or take your frites over the top with a drizzle of truffle flavored oil. When all else fails, ketchup is a trusty stand-by. Use your favorite store-bought brand, or get adventurous and make your own out of roasted red peppers and roasted garlic.
Don’t Waste the Duck Fat!
After your fries are cooked, turn off the heat and let the duck fat cool so it is easy to handle but not solidified. Strain through a fine-mesh strainer to remove any pieces of potato. Refrigerate until thoroughly chilled and then freeze for a later use.