Make the crust:Blend graham crackers into a fine, flour-like crumb. Reserve 1/3 in a small bowl. Mix remaining 2/3 with melted butter. Press into a greased/lined 9″ springform pan. Bake at 350°F for 15 minutes. Let cool.

Make the fudge:In a saucepan over low-medium heat, stir sweetened condensed milk and chocolate chips until melted and smooth. Remove from heat, stir in butter until melted, then add vanilla.

Layer time:Pour half the fudge over the cooled crust. Freeze 10 minutes.

Add vanilla ice cream:Spread all the vanilla ice cream evenly. Freeze again until slightly firm, about 10 minutes.

Add remaining crumbs and fudge:Sprinkle reserved graham crumbs, then drizzle the remaining fudge. Freeze 5 minutes.

Add chocolate ice cream:Smooth it out across the top. Freeze 4 hours to overnight. Overnight is best!

Make marshmallow topping:In a double boiler, whisk egg whites and sugar until sugar is fully dissolved (rub between fingers to check). Transfer to a stand mixer, add cream of tartar and vanilla, and beat on high for 8–10 minutes until thick and fluffy.

Top and torch:Spread marshmallow cream on top. Freeze for 5 minutes. Use a kitchen torch to toast the top. Slice and serve!