Let’s embark on building this spectacular Layered Ice Cream Birthday Cake! Plan ahead – this takes significant freezing time over possibly 1-2 days.

Prep Pans & Crust: Line four 8-inch round cake pans thoroughly with plastic wrap, leaving overhang on the sides. Place them in the freezer to chill while you make the crust. In a small bowl, mix the 1/2 cup chocolate cookie crumbs and 2 tablespoons melted butter until combined. Press this mixture firmly onto the bottom of one of the chilled, lined pans. Freeze for 15 minutes to set.

Freeze Base Layers: Remove the pan with the crust from the freezer. Take the 1 quart of vanilla ice cream and let it soften just slightly at room temperature (5-10 minutes). Working quickly, press the softened vanilla ice cream evenly on top of the cookie crust. Smooth the top. Cover tightly with plastic wrap and return to the freezer.

Take the remaining two 8-inch round pans lined with plastic wrap from the freezer. Soften the 1 quart chocolate ice cream slightly and press it evenly into one pan. Soften the 1 quart birthday cake ice cream slightly and press it evenly into the other pan. Cover both pans tightly with plastic wrap. Freeze all three ice cream layers (vanilla on crust, plain chocolate, plain birthday cake) for at least 4 hours, or until completely solid.

Stack the Base Cake: Once all layers are frozen solid, prepare to stack. Make sure your 8-inch round brownie layer is ready (if homemade, ensure cooled; if store-bought, ensure it’s the right size). Working quickly, unwrap the ice cream layers. Place the crust/vanilla layer (crust side down) onto a freezer-safe plate or board. Carefully un-mold and place the solid chocolate ice cream layer on top. Place the 8-inch brownie layer on top of the chocolate ice cream, pressing firmly to adhere. Finally, un-mold and place the solid birthday cake ice cream layer on the very top. Wrap this entire tall stack tightly in plastic wrap and immediately return it to the freezer until needed (at least another hour or two to ensure it’s solid).

Make the Topping Structure: Line the 8-inch springform pan (base and sides) with plastic wrap. Place it on a tray filled with ice (or work very quickly in a cold place). Have your 4 pints of Haagen-Dazs ice cream slightly softened (just enough to scoop) and your 12 mini meringues ready. Scoop small balls of the different Haagen-Dazs flavors into the lined springform pan, interspersing them with the mini meringues. Press gently but firmly to fill the pan, mounding the scoops slightly into a “little mountain” shape on top. Cover tightly with plastic wrap and freeze for at least 4 hours, or until completely solid.

Make Stabilized Whipped Cream: Just before final assembly (or up to an hour before), make the frosting. If using sheet gelatine, soften it in a bowl of cold water for 5-10 minutes, then squeeze out excess water. If using powdered, sprinkle it over 1 tablespoon of cold water and let bloom for 5 minutes. Gently warm the softened/bloomed gelatine (brief microwave pulse or over warm water bath) just until dissolved into a liquid, then let cool slightly but remain liquid.

Combine the 1 cup cold heavy cream and 2 tablespoons cane sugar in the chilled bowl of a stand mixer fitted with the whisk attachment. Beat on medium speed for about 30 seconds until slightly thickened. With the mixer running on medium-low speed, slowly drizzle in the cooled, liquid gelatine mixture. Increase speed to high and whip until the cream is stiff and holds its shape firmly (but stop before it looks grainy). Chill this frosting briefly if not using immediately (up to 1 hour).

Final Assembly: Prepare your cake stand by spreading a small dab of the whipped cream frosting in the center (helps anchor the cake). Carefully unwrap the frozen stacked ice cream base. Center it on the prepared cake stand. Working quickly, frost the top and sides generously with the stabilized whipped cream frosting. Use an offset spatula for smoothness.

Carefully unwrap the frozen ice cream/meringue topping structure from the springform pan (use the plastic wrap to help lift it). Gently place this “crown” on top of the frosted base cake. Immediately return the entire assembled cake to the freezer for at least 2-3 more hours (or longer) to ensure everything is frozen solid and the frosting is firm.

Decorate and Serve: Just before serving, remove the cake from the freezer. Place the remaining stabilized whipped cream in a piping bag fitted with a large swirl or star tip. Pipe a decorative border around the base of the cake where the main cake meets the stand. Sprinkle the top ice cream/meringue structure with the 2 tablespoons of mini chocolate chips. Let the cake stand for about 5-10 minutes at room temperature before attempting to slice with a very large, sharp knife dipped in hot water and wiped clean between cuts. Serve immediately