Peel, core, and cut the apples into 1-inch (2.5 cm) pieces.
Peel and cube the butternut squash into 1-inch (2.5 cm) pieces.
Steam the apples and butternut squash together for 10 to 12 minutes, or until soft. Add the raisins and steam for 2 additional minutes. Reserve the liquid from the steamer.
Purée the apple, butternut squash, and raisins in a food processor with 1⁄2 cup (120 ml) of the reserved liquid. Add more liquid as needed to obtain the desired consistency.