Blend pumpkin, sugars, butter, eggs and vanilla in a large bowl with an electric mixer on medium speed. Combine dry ingredients in a small bowl; stir into pumpkin mixture. Add raisins and nuts. Pour into a greased 13"x9" baking pan. Bake at 350 degrees for 35 to 40 minutes, until a toothpick tests clean. Cool. Frost; let stand until set. Cut into squares. Makes 2 to 3 dozen.