Preheat the oven to 350°F/175°C. Set aside your bundt pan, but do not grease it until almost ready to use.
Mash your bananas until smooth, set aside. You can use a fork or a potato masher to mash them.
Whisk the flour, baking soda, salt and spices together. Set aside
In your mixer with the paddle attachment, beat the butter until creamy. Add your sugars and beat on medium speed until pale and fluffy, 2-3 minutes.
Add the vanilla, then add the eggs one at a time, beating well after each addition.
Turn the speed to low and add your mashed bananas, your mixture might be lumpy which is fine!
Add the dry ingredients in three additions on low speed, alternating with the sour cream, starting and ending with the dry ingredients.
Fold in your chocolate chips
Use vegetable oil to grease your bundt pan, use a pastry brush to make sure all the nooks and crannies are greased.
Pour the batter into your pan and tape it on the counter to remove any air bubbles.
Bake for 65-75 minutes, a toothpick inserted will come out with a few crumbs. If it is browning too quickly, place some foil on top
In a small saucepan, bring your heavy cream to a simmer (not a boil!). Place your chopped chocolate in a medium bowl, and pour the heavy cream on top. Leave for 3 minutes. With a rubber spatula, swirl the two together until it is completely smooth. Sprinkle over your salt. Let it sit until it is a harder consistency, about 15 minutes. Pour over your cooled bundt pan.
Notes
My recipes have been developed and tested in metric grams. I highly recommend using a weighing scale and measuring out your ingredients the metric way. I have provided a conversion to US cups but please note that I haven't tested the recipe with this method. Butter: I use European style butter, like Kerry Gold, in my recipes. This will make your finished bake much creamier and richer.Salt: If you don't have kosher salt, halve the amount of salt called for in the recipe. 1 teaspoon kosher salt = ½ teaspoon fine salt.Storage: Keep cake covered at room temperature for up to 4 days. Freezing: Slice the cake and wrap in plastic wrap, freeze for up to 3 months. Defrost in the fridge overnight before eating.