When I was studying at the International Culinary Center, my main form of physical exercise was hand-whisking mayo. Making mayo by hand isn’t hard, but it requires some serious forearm strength for around five minutes straight. Considering that at home I can’t be encouraged to whisk faster by an instructor looking over my shoulder, I found another way to make mayo. By using a food processor, you can make your own mayo in barely any time at all.
To properly emulsify two liquids that don’t easily combine, furious agitation is required. Think of it like shaking separated oil and vinegar to combine a salad dressing. Since mayo has much more oil than other ingredients, it’s even harder to emulsify than a vinaigrette, and essentially requires some wild whipping action. It’s very easy for one’s arm to get tired, but whisking too slowly can encourage the mayo to break, leaving a pool of lumpy pockets of oil, egg, and lemon juice. Using a food processor allows electricity to do the work, so you can save your energy for the important stuff, like eating. PS: This method also works with an immersion blender or a standing blender.
When making mayo, I like the neutral flavor of grapeseed oil (you can also use canola oil, which is similarly neutral in flavor but slightly less rich-tasting, or the very flavorful olive oil). Also, since you will be using raw egg yolk in the recipe, it’s best to use pasteurized eggs to reduce the risk of foodborne illness like salmonella.
Place 1 room temperature egg yolk, 1 tablespoon grapeseed oil, 2 teaspoons dijon mustard, 1 tablespoon lemon juice, ½ teaspoon kosher salt, a few grinds of black pepper, and a small splash of white vinegar in a food processor fitted with a metal blade. Cover the food processor with one of the lids that has holes or an opening in the top (like the feed tube lid). Pulse the mixture a few times just to combine the ingredients.
With the motor of the food processor running, slowly stream in 1 cup oil. As the oil slowly mixes with the egg mixture, the mayo will emulsify, suspending tiny droplets of the oil within the egg and lemon juice.
After about 2 minutes, the mayo will have be light and thick. Taste the mayo and add a bit more mustard, salt, or lemon juice as you see fit. It will likely be a bit more yellow than the jarred stuff you can buy at the grocery store, but it will taste about a hundred times better.