01 - Preheat the oven to 350°F (175°C). Generously grease and flour a 10-inch Bundt pan, ensuring every crevice is coated to prevent sticking.
02 - In a large mixing bowl, sift together the all-purpose flour, unsweetened cocoa powder, baking powder, baking soda, and salt. Whisk until evenly distributed and no lumps remain.
03 - Using a stand mixer or hand mixer, beat the softened unsalted butter and granulated sugar on medium-high speed until pale, light, and fluffy, approximately 3 to 4 minutes.
04 - Add the eggs one at a time, mixing thoroughly after each addition until fully incorporated. Blend in the vanilla extract.
05 - With the mixer on low speed, add the dry ingredient mixture in three additions, alternating with the sour cream and whole milk in two additions, beginning and ending with the dry ingredients. Mix just until combined — do not overmix.
06 - Pour the batter into the prepared Bundt pan, smoothing the top with a spatula. Tap the pan gently on the counter to release any trapped air bubbles.
07 - Bake on the center rack for 45 to 50 minutes, or until a wooden toothpick inserted into the thickest part of the cake comes out clean. The cake should spring back lightly when pressed.
08 - Allow the cake to cool in the pan for 10 minutes. Run a thin knife around the edges, then invert onto a wire cooling rack. Let cool completely before glazing.
09 - Heat the heavy cream in a small saucepan over medium heat until it just begins to simmer — do not boil. Pour the hot cream over the semi-sweet chocolate chips in a heatproof bowl. Let stand for 2 minutes, then stir gently from the center outward until smooth and glossy. Allow to cool slightly until it reaches a thick, drizzleable consistency.
10 - Place the cooled cake on a serving plate or wire rack set over parchment paper. Drizzle the ganache evenly over the top, allowing it to cascade naturally down the sides and center of the Bundt cake.
11 - Arrange candied cherries, cranberries, and green candied fruit around the top ring of the cake to resemble a festive wreath. Tuck small sprigs of fresh rosemary or mint between the fruits for a natural holly effect. Dust lightly with powdered sugar for a snow-kissed finish.