01 - Preheat your oven to 350°F (175°C). Line an 8-inch (20 cm) square baking pan with parchment paper for easy removal.
02 - In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, unsweetened cocoa powder, baking powder, baking soda, and salt until well combined.
03 - Add the whole milk, vegetable oil, large egg, and vanilla extract to the dry ingredients. Mix until a smooth batter forms. Gently stir in the hot water until just incorporated; the batter will be thin.
04 - Pour the batter into the prepared baking pan. Bake for 20–22 minutes, or until a toothpick inserted into the center comes out clean. Allow the cake to cool completely within the pan.
05 - Once the cake has cooled, evenly distribute the roughly chopped chocolate sandwich cookies over the surface. Drizzle with peppermint extract and press lightly to adhere them to the cake.
06 - In a small saucepan, combine the granulated sugar and water. Heat over medium heat, stirring only until the sugar dissolves. Continue to cook without stirring until the sugar syrup turns a golden amber color, approximately 4–5 minutes.
07 - Immediately pour the hot caramel onto a separate parchment-lined baking sheet. Swiftly sprinkle the chopped roasted almonds and crushed peppermint candies over the caramel. Allow it to cool completely until hardened, then break into irregular shards.
08 - Melt the semisweet chocolate chips in a microwave-safe bowl using 30-second intervals, stirring between each interval until smooth and fully melted. Artistically drizzle the melted chocolate over the cookie-topped cake layer.
09 - Arrange the hardened brittle shards on top of the melted chocolate, pressing gently so they stand upright and create an appealingly scattered effect.
10 - Refrigerate the confection for 15 minutes to allow the chocolate to set firmly. Once set, slice into portions and serve.