If using sour milk: place 1 tablespoon of white vinegar in a measuring cup and fill with enough milk to make 1 cup. Stir few times and let sit for 2 to 3 minutes.
In a large mixing bowl, whisk together the dry ingredients (flour, baking powder, soda and salt). Set aside.
Generously grease and flour the bundt pan. Set aside.
In a large mixing bowl of a stand mixer, beat together butter and sugar until light and fluffy.
Add eggs, one at a time, beating well after each addition.
Add vanilla and beat well again.
With the mixer on low speed, add the dry ingredients alternating with buttermilk. Increase the speed to medium and beat for 2 minutes.
Stir in cranberries.
Pour the batter into prepared pan.
Bake for 40 to 50 minutes, or until the toothpick inserted in the center comes out clean.
Cool the cake for 2 minutes in the pan. Place a cake plate over the top of the pan and carefully flip it upside down. If the cake won't release right away, tap the pan gently until it does. Cool cake completely before glazing.
!to make the glaze:
Melt chocolate and cream in a double boiler.
Let cool slightly.
Whisk in powdered sugar.
Glaze the cake.
Notes
If using sour milk: place 1 tablespoon of white vinegar in a measuring cup and fill with enough milk to make 1 cup. Stir few times and let sit for 2 to 3 minutes.