A simple version of the classic French dessert buche de Noel, this enchanting cake covered with crunchy almonds and creamy frosting calls to mind a snow-covered log in a wintry forest.
Preheat oven to 350 degrees. Coat a 10-by-15-inch jelly-roll pan with nonstick cooking spray; line bottom with parchment paper. Coat paper with cooking spray; set aside.
In a large bowl, whisk egg yolks with 1/2 cup granulated sugar until pale yellow. Whisk in almond extract and flour just until combined (do not overmix); set aside.
Using an electric mixer, beat egg whites and salt until soft peaks form. While beating, slowly add remaining 1/4 cup granulated sugar (1 tablespoon at a time) and beat until stiff and glossy. Whisk one third of beaten egg whites into yolk mixture; gently fold in remaining whites with a rubber spatula. Spread batter evenly in prepared pan; bake until center of cake springs back when lightly pressed, 15 to 17 minutes.
Immediately after removing cake from oven, run a knife around edge of pan. Dust top of cake with confectioners' sugar; invert cake onto clean parchment paper, and gently peel off the lining paper that's now on top of cake. Starting from a short side of cake, gently roll cake, along with clean paper, into a log; let cool, seam side down, 30 minutes.
Once cake has cooled, prepare filling and frosting. Gently unroll cake, and spread with filling, leaving a 1/2-inch border; starting from a short side, carefully re-roll (do not roll paper in cake), and place, seam side down, on a baking sheet or serving platter. Spread log with frosting; sprinkle with almonds. Refrigerate for at least 2 hours and up to overnight.
To serve, use a serrated knife to slice off the ends of the log neatly, revealing interior. Dust with confectioners' sugar, and, if desired, garnish with Marzipan Mushrooms.
Trim the ends of this showstopping dessert to reveal swirls of chocolate-nut filling.