Coat 4 1/2 quart slow cooker with nonstick cooking spray, turn to "high."

Combine flour, baking powder, baking soda, salt, and pumpkin pie spice in mixing bowl.

Beat sugar and butter in large bowl with electric mixer for about 3 minutes, until light.

Add eggs, one at a time, mixing well after each one.

Add packed pumpkin, blend until well mixed.

Gradually add flour mixture and beat at low speed for a minute or so until smooth.

Spread evenly in slow cooker and cover.

Cook on high setting 2 hours or until center-inserted tooth pick comes out clean.

Let cake stand, uncovered 10 minutes.

Invert onto wire rack, invert again onto serving plate.

Drizzle half of caramel sauce over cake. Serve warm with additional sauce.