Preheat oven to 350°F. Grease a 13 x 9-inch baking pan.
Melt butter and unsweetened chocolate in medium saucepan over low heat until smooth. Let cool 15 minutes.
Stir in sugar, eggs, vanilla and salt. Stir in mashed potatoes until smooth.
Add flour and stir to combine. Pour into prepared baking pan.
Sprinkle with chocolate chips and walnuts. Bake until brownies are firm when lightly touched, about 25 to 30 minutes. Cool on rack. Cut into squares to serve.
Store in a breathable container - airtight containers will cause brownies to become soggy.
Materials courtesy of the Wisconsin Potato & Vegetable Growers Association. For more information, www.wisconsinpotatoes.com
This farm news was published in the February 1, 2006 issue of Farm World.