Note: Read about making animal-fat mayonnaise for a full recap on the science behind these recipes. The jarred mayonnaise added to the food processor at the start makes it easier to create a more stable emulsion. If you are an experienced mayonnaise-maker who has no problems with mayonnaise breaking on you, you may omit the jarred mayonnaise. The mayonnaise can also be made in a bowl with a whisk. This mayonnaise can be made with vegetable oil in place of the rendered animal fat - though flavor will suffer.