Martha Stewart Baked-Alaska Tree

Directions

• Build the cone mold: Open a manila file folder and roll it into a cone 8 inches across, then tape it shut. Trim the base flat to 7 1/2 inches, fit a matching parchment cone inside and stand it tip down in a pot.
• Make the cookie crumbs: Pulse 9 ounces chocolate-wafer cookies with 1/3 cup sugar in a food processor. Add 1 stick melted butter and 1/2 teaspoon kosher salt, then pulse until the crumbs look moist.
• Layer the ice cream: Spread 3 pints softened chocolate ice cream into the cone in a 1-inch layer, leaving the center hollow. Freeze for 15 minutes, then fill the hollow with 2 pints softened peppermint ice cream.
• Freeze the tree: Pat 1 1/2 cups of the crumbs over the top of the cone. Freeze it upright, point down in the pot, for at least 8 hours and up to 3 days.
• Unmold and coat: Invert the cone onto a serving plate and remove the mold and parchment. Let it soften for 5 minutes, then pat the remaining crumbs over the outside and return it to the freezer.
• Cook the egg whites: Whisk 4 large egg whites and the remaining 1 cup sugar in a heatproof stand mixer bowl set over simmering water. Keep whisking for about 3 1/2 minutes, until the sugar dissolves and the whites feel warm.
• Whip the meringue: Fit the bowl onto the mixer with the whisk attachment and start on low speed, building to medium-high until the whites are foamy. Add 1/2 teaspoon cream of tartar and whip until stiff, glossy peaks form.
• Finish the meringue: Fold in 2 teaspoons cornstarch and 2 teaspoons pure vanilla extract. Then transfer it to a pastry bag fitted with a large round tip, such as an Ateco #806.
• Pipe and torch: Start at the bottom of the tree and pipe upward with the tip held perpendicular, dragging the meringue into teardrop shapes. Lightly brown it with a kitchen torch, then cut a piece from tip to base and slice crosswise to serve.