Prep: 20 minutes plus time to freeze
Bake: 13 minutes
Makes: 9 squares
1 tablespoon unsalted butter, softened, for pan
9 tablespoons sugar
2 eggs, separated
2 ounces unsweetened chocolate
2 tablespoons brewed coffee
1 teaspoon vanilla extract
1/2 teaspoon salt
1/4 cup ground almonds (sold as meal or flour)
2 quarts coffee chip ice cream
Whipped cream, to serve, optional
Chocolate sauce, to serve, optional
1. Prep: Butter an 8-by-8-by-2-inch baking pan. Line the bottom with parchment paper, leaving some overhang. Butter parchment and sprinkle with 1 tablespoon sugar.
2. Whip: Whip egg whites and 2 tablespoons sugar to glossy peaks with an electric mixer.
3. Mix: In a large bowl set over simmering water, melt chocolate with coffee into a paste. Still working over simmering water, stir in yolks, vanilla, salt and remaining 6 tablespoons sugar. Remove bowl from heat. Stir in one-third of the egg whites. Fold in remaining whites, then the ground almonds.
4. Bake: Scrape batter into prepared pan. Bake at 350 degrees until just set, about 15 minutes. Cool. Grasp parchment overhang and lift out the cake.
5. Pack: Line the same pan with plastic wrap, with several inches overhang. Scoop in slightly softened ice cream, pressing firmly and smoothing the top. Set cooled cake on top, sugar-side up. Cover with overhanging plastic wrap. Freeze firm, at least 8 hours.
6. Stack: Unmold and unwrap frozen cake-and-ice-cream square. Set cake-side down on a cutting board. Dip a heavy knife into hot water, wipe dry and slice into 9 squares. Serve with whipped cream and/or chocolate sauce.