This easy homemade mayo tastes much better than store-bought! It's sugar-free, soy-free and made with an egg yolk cooked to a food-safe temperature in the microwave!
Place the egg yolk in a small, microwaveable bowl. (Save the egg white for scrambled eggs or another use.)
Whisk in the water, lemon juice and vinegar. Cover the bowl with wax paper and heat in the microwave until the mixture starts to boil, which should take around 25 seconds. Whisk the egg mixture again and heat for another 5 seconds, or until it starts to bubble again.
Whisk once more, cover, and chill the egg mixture in the refrigerator for 10 minutes.
After 10 minutes, whisk in the salt, basil and garlic powder. Then, very slowly pour the oil into the egg mixture in a thin stream, while whisking constantly. The mixture will emulsify and thicken into a creamy mayonnaise. (If you pour the oil in too fast, it won't emulsify.)
Store the mayo in a covered jar in the refrigerator for up to a week. See notes for what to do if the mayo separates into liquid.
Notes
Don't use extra-virgin olive oil, because the taste will be too strong.
An egg yolk heated to at least 160 degrees F is safe to eat.
Homemade mayo can sometimes liquefy if the emulsion breaks. If that happens, place ½ tablespoon of water in a bowl and slowly whisk in the broken mayo in a thin stream, until the mayo comes together again.