Preheat oven to 375 degrees. Oil an 8x8 or 9x9 square baking pan.
Drain the syrup from one can of yams and place in a food processor with the other can, undrained. Add ½ cup frosting, pumpkin pie spice, salt, and pepper. Process until smooth, scraping down the sides of the bowl as needed. Place the mixture into the prepared baking dish and smooth the top.
Sprinkle the chopped pecans over the top. Melt the remaining ¼ cup frosting in the microwave for a few seconds and drizzle over the top of the pecans. Bake for 30 minutes or until hot.