1 (16 ounce) can pumpkin puree
2 cups milk
1/4 cup brown sugar
2 teaspoons ground cinnamon
Place the pumpkin puree in a freezer bag; store in freezer for at least 24 hours.
Heat the bag of pumpkin puree in the microwave on HIGH to soften, 1 to 2 minutes.
Pour the milk into a blender. Add the brown sugar, cinnamon, and pumpkin; blend until smooth.