Squeeze the lemon and pour the juice into the Mason jar. (I use an old fashioned glass juicer but the picture in the article before the recipe shows you a modern one.)

Pour the olive oil and vinegar into the jar with the lemon juice. Cover and give the jar a shake.

Add tarragon, garlic powder, and a dash of ground pepper if you wish. Shake, and serve.

Store in the fridge. Allow it to sit at room temperature for half an hour to soften the olive oil which will turn solid in the fridge.