The recipe below uses a basic ratio of oil to eggs, but you can experiment with different additions to add flavor. Add herbs and spices, or even a little bit of sweetener.
Start by cracking 2 eggs into a bowl and whisking them together until they are blended.
Add vinegar and dijon mustard (if using).
Slowly drizzle in oil one drop at a time while whisking. Continue adding oil very slowly until the mayonnaise begins to thicken then you can begin adding it a little more quickly. Don't stop whisking/blending until all of the oil is fully incorporated.
The mayo can be stored in a sealed container in the fridge for up to a week.
Notes
For richer mayonnaise, use just egg yolks. For easier mayonnaise, feel free to use the egg yolk and egg white.
If you want to make a flavored mayo, like garlic mayo, add a crushed clove of garlic to the bowl with the eggs. You can also add spices or sweeteners, like a little bit of nutmeg or cinnamon.
You want to use a neutral oil, like canola oil, vegetable oil, or sunflower seed oil. You can also experiment with more flavorful oils, like olive oil or avocado oil, just keep in mind that the mayo will have a stronger flavor.
Once the mayo has cooled, you can add it to salads, sandwiches, or any other dish that you want to top with it. The mayo can be stored in a sealed container in the fridge for up to a week.