Heat oven to 350°F. Line bottom of a 10-inch round springform pan with parchment paper, then lightly spray pan with cooking spray (alternatively, you can use a greased 13 x 9-inch pan).
Cake base: In a large bowl or bowl of a stand mixer, beat cake mix, melted butter and egg until well combined. Spread and press batter evenly into bottom of prepared pan.
Filling: In another large bowl (or clean bowl of a stand mixer), beat cream cheese and pumpkin until well combined. Add melted butter, vanilla and eggs; stir until combined. Stir in powdered sugar and pumpkin pie spice until just combined. Pour batter evenly into pan over cake base.
Bake 1 hour to 1 hour 15 minutes, until center of cake is just set and slightly wobbly (if using a 13x9-inch pan, lessen the baking time to 40-50 minutes). Cool completely on a cooling rack.
Remove sides of springform pan. Serve slices of cake with caramel sauce and candied pecans on top.