Pumpkin Spice Trifle

0 Let the cake cool completely and then slice or crumble into bite-sized pieces. Thaw the whipped topping according to package directions. 
1 In the bowl of a standing mixer with the whisk attachment (or using a hand mixer), beat the softened cream cheese on high until very smooth. Add powdered sugar and beat again until the mixture is smooth, 2 to 3 minutes more, scraping down the sides as needed. Add pumpkin puree, pumpkin pie spice, and vanilla and mix until evenly combined.
2 In a large trifle bowl, layer one third of the cake pieces, half of the frozen whipped topping, and one third of the toffee. Top that with one third of the cake pieces, pressing down gently to compress, then all of the pumpkin mixture, and one third of the toffee. Finally, add another layer of cake and all of the remaining whipped cream. Reserve the last third of the toffee.
3 Refrigerate for at least 4 hours and up to 24 hours. Top with the remaining toffee right before serving. Serve chilled.