Chocolate-Peppermint Layer Cake with Caramelized White Chocolate Buttercream

Preheat oven to 350°F (180°C). Spray 3 (8-inch) round cake pans with baking spray with flour. Line bottom of pans with parchment paper.

In a large heavy-bottomed saucepan, melt butter over medium heat. Whisk in cocoa; cook, whisking frequently, until fragrant, about 1 minute. Remove from heat; whisk in brown sugar, hot coffee, and granulated sugar until sugars dissolve. Whisk in buttermilk, eggs, and extracts.

In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Gradually add flour mixture to cocoa mixture, whisking until just combined. Divide batter among prepared pans (about 621 grams each).

Bake until a wooden pick inserted in center comes out with a few moist crumbs, 25 to 30 minutes. Let cool completely in pans on wire racks. Remove from pans, and level cooled cake layers, if desired.

Place 1 cake layer on a serving platter. Spread 1½ cups (275 grams) Caramelized White Chocolate Buttercream on top. Top with second cake layer, and spread 1½ cups (275 grams) buttercream on top. Top with remaining cake layer. Spread remaining buttercream on top and sides of cake, smoothing with an offest spatula or bench scraper.

To decorate with red food coloring, using a wooden pick, drag food coloring in long lines along sides of cake, if desired (A). Using a bench scraper or long offset spatula, spread food coloring into buttercream in long, smooth motions to create streaks (B). (The more passes you make with bench scraper or spatula, the more the red color will spread, so make as few passes as possible.) Garnish with candies just before serving, if desired. Refrigerate in an airtight container for up to 3 days.

Preheat oven to 250°F (130°C).

In a completely dry 9-inch round cake pan, place white chocolate.

Bake until melted and a light caramel color, about 45 minutes, stirring with a spatula every 10 minutes. (Chocolate might look dry and crumbly at any point but continue stirring until smooth.)

In the heatproof bowl of a stand mixer, whisk together sugar, egg whites, and cream of tartar. Place bowl over a saucepan of simmering water. Cook, stirring frequently, until sugar dissolves and an instant-read thermometer registers 160°F (71°C).

Carefully return bowl to stand mixer. Using the whisk attachment, beat at high speed until mixture has cooled significantly and becomes thick and glossy. Reduce mixer speed to medium-high; add butter, 2 tablespoons (28 grams) at a time, beating until completely combined after each addition. Beat until buttercream is thick and glossy. (It may look slightly curdled at some point, but keep mixing.) Beat in vanilla and salt.

If white chocolate has solidified, transfer to a microwave-safe container, and heat on high in 30-second intervals, stirring between each, until melted. With mixer on medium speed, slowly add white chocolate to buttercream, beating until combined and stopping to scrape bottom and sides of bowl. Use immediately.