3 pounds sweet potatoes, scrubbed
4 tablespoons unsalted butter
1/2 teaspoon ground cinnamon
Large pinch ground allspice
Large pinch cayenne pepper
1/4 cup pecans, very finely chopped
2 scallions, thinly sliced
To serve the potatoes right away instead of freezing them, after processing the potato mixture, transfer it to a serving dish and sprinkle with the pecans and scallions.