- 1 tablespoon cornstarch
- 1 1/2 teaspoons dry mustard, preferably Colman
- 1 teaspoon granulated sugar
- 1/2 teaspoon salt or more to taste
- Pinch cayenne
- 3/4 cup buttermilk
- 1 large egg
- 2 tablespoons fresh lemon juice
- 1 tablespoon extra virgin olive oil
- In a medium saucepan, whisk cornstarch, mustard, sugar, salt, and cayenne.
- Add 1/4 cup of the buttermilk and whisk until you have a smooth paste.
- Add the egg and the remaining 1/2 cup buttermilk and whisk until smooth.
- Set the pan over medium-low heat and cook, whisking until the mixture comes to a simmer and thickens.
- Continue to whisk for 15 seconds, then remove the pan from the heat.
- Whisk in the lemon juice and oil.
- Transfer the mayonnaise to a small bowl and press a piece of plastic wrap directly on the surface to prevent a skin from forming.
- Let cool. Can be stored in the refrigerator for up to 3 days; whisk briefly before using
- Makes 1 cup.