1. Rinse cut potatoes well with cold water to remove the starch (this prevents them from sticking together). Drain and dry completely to avoid splattering.
2. Prepare the mayonnaise: In a blender or food processor (a Vitamix is recommended), combine egg yolks, egg, lemon juice, and vinegar. Blend for 30 seconds. Add canola oil in a slow stream while blending; blend until emulsified. Add salt. Continue to blend while adding olive oil in a slow stream. Finally, slowly add in truffle oil while blending. Add roasted garlic.
3. Heat oil in a deep fryer to 250 degrees Fahrenheit. Add French fries and fry for five to six minutes. Remove from oil and place on a baking sheet. Place sheet in the refrigerator for half an hour, until French fries are cold.
4. Heat oil in a deep fryer to 350 degrees Fahrenheit. Add cooled French fries and fry again for two to three minutes, until golden and crisp. Season with salt, pepper, and parsley. Sprinkle with Parmesan cheese.
5. Serve truffle mayonnaise in a ramekin alongside fries.
When we asked various chefs for French fry tips, they all told us that the best potato to use is the pricey Kennebec. It’s rare to find the Kennebec in grocery stores. Finer restaurants buy these potatoes through suppliers.
Chef José E. Soto recommends D’Allesandro Truffle Oil, the brand used in the restaurant
The truffle mayo will yield about 3 cups, more than you need for the fries. Use it for all your mayo and dipping needs all week, or divide recipe in half (the only challenge will be splitting the whole egg).