Grate the sweet potatoes into pieces about 1 inch long and about 1/4 inch thick. Saute the sweet potatoes in the butter for 5 minutes.
Add the tequila, lime juice and sugar, and cook covered, over moderate heat, for 5 minutes.
* Sweet potatoes sauteed in lime and tequila -- Rose's lime juice, a common brand, has a substantial amount of added sugar. Try to find lime juice without added sugar, or leave all the sugar out of the recipe if you can't find it. Naturally you will get the best results if you squeeze fresh limes to get the lime juice.