Cake

1. Preheat your oven to 325⁰F (160⁰C).
2. Grease your pan really well using Magic Pan Release or butter and flour. 
3. In a large bowl, whisk together 2 cups all-purpose flour, 1/2 cup whole wheat flour, 1/2 cup white sugar, 1/2 cup golden yellow sugar, 1 1/4 tsp baking powder, 1 tsp ground cinnamon, 1/2 tsp salt, and 1/2 tsp baking soda.
4. Break up any brown sugar lumps with the back of a spoon.
5. In another bowl, whisk together 3/4 cup buttermilk, 2 lightly beaten eggs, 2 mashed bananas, 1/4 cup virgin olive oil, and 1 tsp vanilla until smooth. It might look a bit lumpy from the bananas; that’s fine.
6. Pour the wet mixture into the dry ingredients all at once.
7. Beat with a handheld mixer on medium to high speed for about 2 minutes until the batter looks smooth and slightly thick. Don’t overmix, as the cake can turn dense.
8. Spoon the batter into your prepared pan and gently level the top.
9. Bake for 45 minutes, or until a tester inserted into the centre comes out clean or with just a few crumbs. If it’s still wet, give it another 3 to 5 minutes and check again.
10. Turn the oven off and let the cake sit inside for 5 minutes with the door slightly open. This helps prevent sinking.
11. Cool in the pan for 10 to 15 minutes, then carefully turn out onto a wire rack and let it cool completely before adding the ganache. If the cake is warm, the ganache will just run right off.

Ganache

1. In a microwave-safe bowl, combine ½ cup – 100 g chopped dark chocolate and 1/4 cup half-and-half milk.
2. Microwave at 50 percent power for about 1 minute. Stir well. If needed, heat again in 15-second bursts, stirring each time, until smooth.
3. Let the ganache sit for 10 to 15 minutes to thicken slightly. If you’re impatient, pop it in the freezer for a few minutes, but keep an eye on it so it doesn’t firm up too much.
4. Spoon or pour over the completely cooled cake and let it settle naturally.