Prepare the pound cake by slicing it into layers about 1/2 inch thick.

In a medium bowl, combine the pumpkin puree, pumpkin spice, and half of the powdered sugar until well blended.

In a separate bowl, whip the heavy cream, remaining powdered sugar, and vanilla extract until soft peaks form.

Start layering: at the bottom of your trifle dish, add a layer of pound cake slices.

Spoon half of the pumpkin mixture over the pound cake layer, spreading it evenly to cover the cake.

Add a layer of whipped cream over the pumpkin mixture, smoothing it out to create an even surface.

Sprinkle a portion of the mixed berries over the whipped cream, followed by a sprinkle of chopped pecans for crunch.

Repeat the layering process until all ingredients are used, finishing with a layer of whipped cream and garnishing with remaining berries and pecans on top.

Refrigerate the trifle for at least 2 hours before serving, allowing the flavors to meld together.