01 - Preheat oven to 350°F. Generously grease and flour a 10-cup Bundt pan, ensuring every crevice is coated to prevent sticking.
02 - Sift together the all-purpose flour, cocoa powder, baking powder, baking soda, and salt in a medium bowl. Set aside.
03 - Beat the softened butter and granulated sugar in a large bowl 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. Blend in the vanilla extract.
05 - Alternately add the sifted dry ingredients and buttermilk to the butter mixture, beginning and ending with the dry ingredients. Fold gently until just combined — avoid overmixing to keep the crumb tender.
06 - Pour the batter evenly into the prepared Bundt pan and smooth the surface with a spatula.
07 - Bake for 45 to 50 minutes, or until a wooden skewer inserted into the thickest part of the cake emerges clean.
08 - Let the cake rest in the pan for 15 minutes, then carefully invert onto a wire cooling rack. Allow it to cool completely before glazing.
09 - Heat the heavy cream in a small saucepan 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 glossy and smooth.
10 - Drizzle the warm chocolate glaze over the completely cooled cake, letting it flow naturally down the sides.
11 - Lightly dampen the fresh cranberries with water, then roll them in granulated sugar until evenly coated. Arrange the sugared cranberries and rosemary sprigs on top of the glazed cake to mimic a Christmas wreath. Finish with a light dusting of powdered sugar for a snowy effect.