Method:

• Heat oven to 350°F (180°C). Grease bottoms and sides of three 8-inch or 9-inch (20 or 22 cm) round pans with shortening (do not use cooking spray); lightly flour.
• In large bowl, beat cake mix, water, oil, 1 tablespoon (15 mL) liqueur and eggs with electric mixer on low speed 30 seconds. Beat on medium speed 2 minutes, scraping bowl constantly.
• Pour about 1 3/4 cups (425 mL) batter into each pan. (If baking only 2 pans at one time, refrigerate remaining batter until ready to use.)
• Bake about 24 minutes or until toothpick inserted in centre comes out clean. Cool 10 minutes.
• Run knife around sides of pans to loosen cakes; remove from pans to wire rack. Cool completely, about 1 hour.
• Meanwhile, in 2-quart (2 L) saucepan, mix 1/4 cup (50 mL) of the whipping cream, the granulated sugar and 1/3 cup (75 mL) liqueur. Cook over medium heat, stirring constantly, until sugar is dissolved and mixture simmers; remove from heat.
• Stir in chocolate chips with wire whisk until chips are melted. Stir in 2 teaspoons (10 mL) vanilla.
• Pour into large bowl; cool about 10 minutes or until room temperature.
• In chilled medium bowl, beat remaining 1/2 cup (125 mL) whipping cream on high speed just until soft peaks form. Fold whipped cream into chocolate mixture. Cover and refrigerate 30 minutes.
• In chilled medium glass or metal bowl, beat all topping ingredients on high speed until soft peaks form.
• Fill cake layers with mousse. Spread topping over side and top of cake. Cover and refrigerate at least 2 hours before serving. Store covered in refrigerator.