Yeah, you can use whatever fat or oil you want. The process is just to emulsify it into egg yolks. This is the recipe I have saved for it:
## Mayonnaise
### Ingredients
- 3 egg yolks
- 2 tbsp lemon juice
- 2 tbsp mustard
- ½ tbsp salt
- ¾ cup beef tallow, liquified and cooled
### Directions
1. Mix yolks, lemon juice, mustard, and salt.
2. Slowly add fat to mixer on medium speed to emulsify.