Why do gazpacho recipes have you put garlic and salt together, then mash with an egg? Why do gazpacho recipes have you put garlic and salt together, then mash with an egg?

What is the purpose?
Salt acts as a mechanical agent to help you make a paste out of the garlic. It prevents the garlic cloves from slipping against the mortar walls, and helps with the grinding and mashing. Salt+garlic is a common start for a number of mortar/pestle recpies in Spain.