- Line an 8 ½ x 4 ½ inch loaf pan with two crossed pieces of plastic wrap, allowing for ample overhang on all sides of the pan. Set aside.
- Place ¾ cup cream in a small saucepan and bring to a simmer over medium low heat. Remove pan from heat and pour in chocolate chips. Allow to steep for 5 minutes then whisk until smooth. Set aside to cool completely. Once cool, whisk in ¼ cup room temperature liqueur.
- In a large bowl, add one cup cream, 2 tablespoons powdered sugar and ½ teaspoon vanilla extract. Beat on high speed using whisk attachment until soft peaks start to form. Pour in ¼ cup liqueur and continue to beat until stiff peaks form.
- Place ½ cup whipped cream in bottom of prepared loaf pan. Smooth to level. Top with a layer of graham crackers, using a serrated knife to cut pieces to fit. Top graham crackers with 2/3 cup chocolate mixture. Smooth to level. Top with layer of graham crackers. Repeat layers – cream, cracker, chocolate, cracker – ending with cream.
- Freeze cake for at least 8 hours or overnight.
- About 10 minutes before removing cake from freezer, place remaining cream, powdered sugar and vanilla extract in a large bowl. Beat on high speed using whisk attachment until soft peaks start to form. Pour in remaining ¼ cup liqueur and continue to beat until stiff peaks form.
- Remove cake from freezer and place upside down on a platter. Remove pan from cake and peel plastic wrap from cake. Frost with whipped cream and return to freezer for at least 2 hours.
- Use a serrated knife to cut slices when ready to serve.
Note: Allow two days to make this cake