01 - Preheat oven to 350°F. Generously grease and flour a 10-cup Bundt pan, ensuring every crevice is coated to prevent sticking.
02 - In a medium bowl, sift together the all-purpose flour, cocoa powder, baking powder, baking soda, and salt. Set aside.
03 - In a large mixing bowl, beat the room-temperature butter and granulated sugar together using an electric mixer until pale, light, and fluffy, approximately 3 minutes.
04 - Add the eggs one at a time, beating thoroughly after each addition until fully incorporated. Stir in the vanilla extract.
05 - Alternately add the sifted dry ingredient mixture and the buttermilk to the butter mixture, beginning and ending with the dry ingredients. Fold gently until just combined; avoid overmixing to maintain a tender crumb.
06 - Pour the batter evenly into the prepared Bundt pan, smoothing the surface with a spatula to ensure uniform baking.
07 - Bake on the center rack for 45 to 50 minutes, or until a wooden skewer inserted into the thickest part of the cake emerges clean.
08 - Allow the cake to rest in the pan for 15 minutes, then carefully invert onto a wire cooling rack. Let cool completely before glazing.
09 - In a small saucepan, heat the heavy cream over medium heat until just steaming. Pour the hot cream over the chocolate chips and butter in a heatproof bowl. Let stand for 2 minutes, then whisk until smooth and glossy.
10 - Drizzle the warm chocolate glaze over the fully cooled cake, allowing it to flow naturally down the sides for an elegant finish.
11 - Lightly dampen the fresh cranberries with water, then roll in granulated sugar to create a frosted effect. Allow to dry on a wire rack. Arrange the sugared cranberries and rosemary sprigs artfully around the top of the cake to resemble a Christmas wreath. Finish with a light dusting of powdered sugar for a snowy presentation.