Add all ingredients except for oil to a food processor or blender. Process for 30 seconds in the food processor or 10 seconds in the blender. With the motor running, add the oil in a thin, steady stream until all the oil is added and the mixture is smooth. Stop the motor and taste. If the sauce it too thick, thin it with a little hot water. if too thin, process a little longer. Add lemon, thyme, salt, and pepper. The mayonnaise can be refrigerated in an airtight container for up to 1 week.