My family and I were traveling through Southern California and we stopped at a random steakhouse and had mashed sweet potatoes JUST LIKE THESE. I guessed on the ingredients and they turned out fabulous.
lbs sweet potatoes, quartered lengthwise, and cut into 1/4 inch-thick (2 large or 3 medium to small potatoes) or 2 lbs yams, peeled quartered lengthwise, and cut into 1/4 inch-thick (2 large or 3 medium to small potatoes)