✓ Preheat oven to 350°F (175°C) and line baking sheets with parchment.

✓ Mix butter and sugar until pale and fluffy, about 2 minutes.

✓ Add egg and vanilla; beat until fully incorporated.

✓ Sift flour and fold into butter mixture just until combined.

✓ Stir in peppermint extract and optional sprinkles until evenly colored.

✓ Portion dough onto sheets, flatten to ¼‑inch thickness; bake 10‑12 minutes until edges turn light golden brown.

✓ Combine crushed chocolate sandwich cookies with sweetened condensed milk in a saucepan; heat over low heat, stirring until smooth.

✓ Melt chocolate with half of the chocolate chips, stir in crushed candy canes, then let cool until set.

✓ Prepare cake mix according to package, adding butter and eggs; pour into a 9‑inch round pan and bake 25‑30 minutes until a toothpick comes out clean.

✓ Whisk cream cheese with a splash of milk until smooth; fold in remaining chocolate chips for speckled frosting.

✓ Cut cooled cookies into festive shapes and set aside.

✓ Spread condensed‑milk cookie layer onto parchment; smooth and refrigerate 15 minutes.

✓ Pour melted chocolate over the set layer, sprinkle additional crushed candy canes, and cool 20 minutes.

✓ Slice chilled chocolate bark into bite‑size squares and arrange on a platter.

✓ Drizzle remaining melted chocolate over baked cake, swirl for marble effect, and let set 10 minutes.

✓ Pipe colored frosting onto the cake in decorative ribbons and sprinkle extra sprinkles if desired.

✓ Fill each mini tart shell with pastry cream, top with fresh fruit, and press gently to settle.

✓ Place a layer of peppermint cookies on a large platter, adding dollops of cream cheese frosting between rows.

✓ Arrange chocolate bark squares around the perimeter, scattering crushed candy canes for sparkle.

✓ Center the frosted cake on the platter, surround with mini fruit‑topped tarts, and finish with fresh berries and a sprig of rosemary.