Step 1

Combine Ingredients: In a tall container, such as a mason jar, add the egg, Dijon mustard, vinegar, lemon juice, and salt.

Step 2

Pour the oil over the top of the ingredients and let it rest for 15 seconds so the ingredients can settle.

Step 3

Insert the immersion blender into the container, touching the bottom. Start blending without moving the blender for about 10 seconds until the mixture begins to emulsify. Slowly lift and tilt the blender to incorporate the rest of the oil. Continue blending until thick and creamy.

Step 4

Taste the mayonnaise. Add more lemon juice, sugar, or salt to balance the flavors, if desired. Transfer the mayonnaise to a clean, airtight container. Refrigerate and use within 1 week.