01 - Preheat oven to 350°F. Grease and flour a 10-cup Bundt pan thoroughly, ensuring all crevices are 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 bowl, beat the room-temperature butter and granulated sugar with an electric mixer until light and fluffy, approximately 3 minutes. Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
04 - Alternately add the sifted dry ingredient mixture and the buttermilk to the creamed butter mixture, beginning and ending with the dry ingredients. Mix until just combined — do not overmix, as this will produce a dense crumb.
05 - Pour the batter evenly into the prepared Bundt pan, smoothing the top with a spatula. Bake for 45 to 50 minutes, or until a wooden skewer inserted into the center comes out clean.
06 - Allow the cake to cool in the pan for 15 minutes, then carefully invert onto a wire cooling rack. Let cool completely before glazing.
07 - In a small saucepan, heat the heavy cream over medium heat until just steaming — do not boil. Pour the hot cream over the chocolate chips and butter in a heatproof bowl. Let sit for 2 minutes, then whisk until smooth and glossy.
08 - Drizzle the chocolate glaze over the fully cooled cake, allowing it to flow naturally down the sides for an elegant drip effect.
09 - Lightly dampen the fresh cranberries with water, then roll them in granulated sugar until evenly coated. Let dry on a wire rack. Arrange the sugared cranberries and rosemary sprigs around the top of the cake to resemble a holiday wreath. Dust lightly with powdered sugar for a snowy finish.