4ouncessemisweet premium chocolate - ideally ScharfenbergerGhirardelli or Lindt
Preheat oven to 275 degrees. Thoroughly grease and flour a 12 cup non-stick bundt pan - or spray with nonstick baking spray.
In a small bowl, mix mashed bananas, lemon zest and lemon juice, set aside.
In a medium bowl, mix dry ingredients: flour, baking soda and salt. Set aside.
In a large bowl, cream butter and sugar until light and fluffy, about 3 minutes. Add eggs one at a time, incorporating each before adding the next. Stir in vanilla.
Blend 1/3 of flour mixture and then add 1/3 buttermilk until just blended. Alternate flour and buttermilk until batter is just combined, but be careful not to over-beat.
Add banana mixture to batter and mix until just combined.
Pour batter into prepared pan and bake in preheated oven for 1 hour and 40 minutes or until a toothpick inserted in the center of cake comes out clean.
Transfer the cake from the oven directly to the freezer (still in the pan) for 45-60 minutes. After cooling in the freezer, transfer cake to a cooling rack for at least 3 hours.
Meanwhile, prepare the ganache. Heat cream in a small saucepan over medium heat, until hot, but not boiling. While cream is heating, finely chop chocolate on a cutting board and transfer to a small bowl. Pour hot cream over chocolate and let it set for a few minutes until the chocolate softens. Use a whisk to carefully incorporate the cream into the chocolate until glistening and smooth.
Invert the cake onto a cake plate or pedestal.
Spoon ganache over the cooled cake, so that it runs over the ridges.
Store cake covered in the refrigerator for up to 3 days. Good luck getting it to last that long.
Jamie (My Baking Addiction) says that putting the cake in the freezer is what makes the cake so moist. I think the low oven temp would prevent it from drying out as well.