- For the base:
- 4 ounces (1/2 cup) butter, cubed
- 1/4 cup granulated sugar
- 5 tbsp unsweetened cocoa powder
- 1 egg, lightly beaten
- 1 1/2 cups graham cracker crumbs
- 1/2 cup finely chopped nuts (recommended: pecans or walnuts)
- For the pumpkin layer:
- 4 ounces butter, at room temperature
- 1/4 cup pumpkin puree (not pumpkin pie filling)
- 1 tsp ground cinnamon
- 1/2 tsp ground nutmeg
- 1/2 tsp ground ginger
- 1 tsp vanilla extract
- Pinch salt
- 2 tbsp instant vanilla pudding dry mix
- 1 lb (4 cups) powdered sugar, sifted
- For the chocolate topping:
- 6 ounces semi-sweet chocolate, finely chopped
- 1 tbsp butter
1. To make the bottom layer: prepare an 8x8 pan by lining it with aluminum foil and set aside. Combine the graham crumbs and chopped nuts in a large bowl.
2. Fill a saucepan with about an inch of water, and place it over medium-low heat. Fit a double boiler or close-fitting metal bowl on top, and place the butter, sugar, and cocoa in the double boiler. Stir occasionally until the butter is melted and the mixture is entirely smooth.
3. Add the beaten egg to the cocoa mixture and stir continuously until it cooks and thickens. This process should take 2-4 minutes. The mixture will get very thick and shiny. If the fat seems to separate out, continue stirring or whisking until it reincorporates. Removing it from the heat briefly might help everything come back together.
4. Once cooked, scrape the cocoa mixture into the bowl with the graham crumbs and nuts and stir to combine. Once there are no dry patches in the ingredients, scrape the candy into the prepared pan and use your hands to press it into an even layer. Set it aside while you prepare the pumpkin layer.
5. To make the pumpkin layer: Place the softened butter in the bowl of a large stand mixer fitted with the paddle attachment, and beat it until the butter is creamy. (Alternately, you can use a hand mixer and a large bowl.)
6. Add the pumpkin puree, powdered sugar, vanilla pudding mix, cinnamon, nutmeg, ginger, salt, and vanilla extract, and beat on low until combined. Scrape down the bowl, and then turn the mixer to medium, beating for about a minute until the candy has lightened in color and texture.
7. Spoon the pumpkin buttercream out onto the crust and smooth it into an even layer. Refrigerate the candy until the buttercream layer is firm, at least 30 minutes.
8. To finish the bars, combine the chopped chocolate and butter in a bowl and microwave in 20-second intervals, stirring after every 20 seconds, until the chocolate is melted and smooth. Pour it over the pumpkin buttercream and smooth it into an even layer.
9. Refrigerate the pan to set the chocolate. Once completely set, remove the bars from the pan using the foil as handles. Use a sharp chef's knife to cut the candy into small 1-inch squares to serve. If the chocolate cracks, let the candy sit at room temperature and soften for a few minutes.
10. Store Pumpkin Nanaimo Bars in an airtight container in the refrigerator for up to two weeks. For best results, let them sit at room temperature for a few minutes before serving.