Preheat oven to 350 degrees.
In a large bowl, add cake mix, pumpkin, eggs and pumpkin pie spice. Beat with a hand mixer on low until moistened, then continue on medium speed for 2 minutes.
Pour batter into a greased 9x13 baking pan. Bake at 350 degrees for 20-25 minutes, or until a toothpick inserted comes out clean.
Let cake cool completely. When cool, cut into 1 inch squares.
While cake is cooling, make filling.