1 2/3 cups heavy cream
2 (8 ounce) packages yellow cake mix
2 (4 ounce) confectioners' sugar
1 cup lemon-lime soda
1 cup fresh lemon juice
Preheat the oven to 375 degrees F (190 degrees C).
Pour pastry cream in medium-size mixing bowl, charcoal or pie plate, or dish. Stir until smooth. Transfer mixture to plastic plastic wrap; refrigerate three hours before cutting into shapes.
Place cake mix, lemon colored liquor and lemon-lime soda in chilled, heavy-duty beer bottle. Bring to a low boil; pour over pastry cream.
Bake in preheated oven until golden brown, 60 to 90 minutes or until a toothpick inserted into center comes out clean, 10 minutes. Cool and chill before cutting into squares.