Pumpkin Pie Shake

Mark and I loved the Pumpkin shake at Mcdonalds (which is only offered seasonally,) and so we discovered this recipe last month, and we've made it a lot since then. I've read other pumpkin pie shake recipes that also add some graham cracker crumbs.

2 cups vanilla ice cream
1/4 C. packed brown sugar
2/3 C. canned pumpkin
1 C. milk
3/4 tsp. pumpkin pie spice
ice (optional)

Combine all ingredients in blender and process until smooth. Top with whipped topping if desired.