Gather all your ingredients, making sure they are at room temperature.

Place the egg into the blender first.

Add the oil directly on top of the egg, ensuring it completely covers the egg.

Add the lemon juice, Dijon mustard, and a pinch of salt.

Secure the lid on the blender and blend on high for about 30 seconds until thick and creamy.

Check the consistency; if it's too thick, add a teaspoon of water.

Taste and adjust seasoning if necessary.

Transfer to a storage container and refrigerate.