Chop two bars of semisweet chocolate and toss them into a heat-proof bowl.

Cook 1 cup of heavy cream in a saucepan over medium heat. Once it bubbles, immediately pour it into the chocolate bowl.

Let it soak for a couple of minutes. Then, gently whisk it so the chocolate can melt and blend in the cream nicely. You’ll get about 1 ½ cups of chocolate ganache.

Divide half of the ganache (¾ cup) into a separate bowl and let it sit at room temperature without cover for at least 30 minutes. Cover the remaining ganache tightly and pop it into the fridge for topping later.

Preheat your oven to 350°F or 177°C. Generously grease a 10-inch Bundt cake pan with nonstick cooking spray.

Mash 3-4 ripe bananas smoothly using a blender, mixer, food processor, or fork. It yields about 1 ½ cups.

In a medium bowl, stir the all-purpose flour, cinnamon, baking soda, baking powder, and a pinch of salt together. Set aside.

Beat ¾ cup of unsalted butter in a mixing bowl on high for 1 minute using a stand or handheld mixer with a paddle attachment. Once it’s creamy, fold in 1 cup of granulated sugar and ½ cup of brown sugar on high for around 2 minutes until combined. Scrape down the bowl in between.

Mix in 3 eggs and 2 teaspoons of vanilla extract at medium-high speed until incorporated. Then, fold in the mashed bananas. Scrape down the bowl when mixing.

Reduce the mixer to low speed. Add the dry ingredients and buttermilk in three parts. Gently mix each addition until blended. You’ll get about 6 cups of thick cake batter.

Pour ⅓ of the batter into the greased Bundt pan, then top it with ½ of the chocolate ganache. Use a toothpick or the point of a knife to swirl the mixture to create the marble pattern. Continue with ⅓ of the batter and the remaining ganache and finish with the rest of the batter. Swirl everything again.

Bake it for 60 to 75 minutes, depending on your oven. If you notice the cake browns too fast, loosely cover it with aluminum foil for even baking. The cake is ready if a toothpick poked into it comes out clean or with a few moist crumbs.

Take the pan out of the oven and let the cake rest for 2 hours. Then, free it from the pan and allow it to cool completely on a wire rack.

Remove the ganache from the fridge. Reheat it over low heat or in a microwave with 10-second bursts until it reaches a drizzle-able consistency. Drizzle the chocolate ganache over the cake, slice, and enjoy!