Preheat oven to 350°F and line muffin tins with cupcake liners.
In a large bowl, combine cake mix, oil, milk, eggs, pumpkin puree, and pumpkin pie spice. Mix until smooth.
In a separate bowl, beat cream cheese, sugar, egg, and vanilla until smooth.
Fill cupcake liners 2/3 full with pumpkin batter.
Add a spoonful of cream cheese mixture on top of each cupcake and swirl gently with a toothpick.
Bake for 17–20 minutes or until a toothpick inserted in the center comes out clean.
Let cool completely before serving.