- In a small saucepan over medium heat, melt the butter. Add the cocoa and sugar, whisking until well combined and the sugar is melted. Add vanilla.
- Place the egg in a bowl and whisk in a couple of spoonfuls of the hot cocoa mixture. Then pour the egg mixture into the cocoa mixture over medium heat, whisking constantly. The mixture will thicken quickly; remove from the heat so that the eggs do not curdle and become lumpy.
- Pour the butter mixture into the graham cracker mixture and stir thoroughly to combine. Pour into the prepared pan, and press down to make an even layer.
- Melt the 1/2 c butter (about 20 seconds in the microwave). Add creme de menthe and 3 c powdered sugar and beat with a mixer.
- Spread on top of the crust (it will be runny). Chill 1 hour in the refrigerator until good and firm.
- Melt the 1/4 c butter and chocolate chips on the stove just to the melting point, so that the chocolate is not too hot. It will be a really thick paste.
- Spread *seriously* fast on chilled mint layer.
- Chill at least 20 minutes, but cut the bars before it gets too cold (check every 10 minutes after the first 20).
Source: Based on https://thenovicechefblog.com/easy-nanaimo-bars/