Separate the egg yolk and egg white. Add the egg yolk to a bowl.
Add a little lime juice, olive oil, sugar, and salt to the egg yolk bowl and whisk all the ingredients to combine.
Once the oil is fully incorporated, add more lime juice, olive oil, sugar, and salt. Continue whisking the mixture.
Repeat this process until you run out of ingredients, and the mixture reaches a thick, buttery consistency.
The process is the same as the hand mixer method. However, you'll have to whisk the mixture by hand, which takes more time and effort.
Store the sốt bơ trứng in a closed glass or plastic container and refrigerate for up to 2 weeks.