Banana Chocolate Chip Layer Cake

Ingredients

• ½ cup (1 stick or 115 g) butter, softened to room temperature
• ½ cup (100 g) light or dark brown sugar
• ¾ cup (150 g) granulated sugar
• 3 eggs, room temperature
• 1½ cups mashed banana (about 3 large very ripe bananas)
• 2 tsp vanilla extract
• 2 cups (250 g) all-purpose flour
• 1 tsp baking soda
• ½ tsp ground cinnamon
• 1 tsp salt
• ½ cup (120ml) buttermilk
• 1 cup (180g) mini or regular-size chocolate chips

• 1¼ cups (290 g) butter, softened to room temperature
• 4 cups (375–500 g) confectioners’ sugar
• ¾ cup (95 g) unsweetened cocoa powder
• 5 tbsp heavy cream (or half-and-half )
• 1 tsp vanilla extract
• ¼ tsp salt

1. Adjust the oven rack to the lower third position and preheat the oven to 350°F.
2. Generously coat two 9 x 9 x 2in round baking pans with non-stick cooking spray. Set aside.
Make the cake
3. Using a handheld or stand mixer fitted with a paddle attachment, beat the butter, brown sugar, and granulated sugar together in a large bowl on medium speed until creamed, about 2–3 minutes. Add the eggs, one at a time, beating well on low speed after each addition. Add the mashed bananas and vanilla, beating on low speed for about 1 minute.
4. Whisk the flour, baking soda, cinnamon, and salt together in a medium bowl. Slowly add the dry ingredients to the wet ingredients in three additions, stirring by hand after each one. Add the buttermilk and stir until combined. The batter will be lumpy. Fold in the chocolate chips.
5. Divide the batter evenly into the prepared cake pans. Bake side by side until a wooden toothpick inserted in the center of the cakes comes out clean, about 22–24 minutes. Allow to cool completely in the pans set on a wire cooling rack.
Make the frosting
6. Using a handheld or stand mixer fitted with a paddle attachment, beat the butter in a medium bowl on medium speed for 3–4 minutes. Add 3 cups of confectioners’ sugar and ¾ cup of cocoa powder. Mix on low. Add 3 tablespoons of heavy cream and the vanilla extract. If the frosting is too thin, add more (up to 1 cup) of confectioners’ sugar until you get the desired consistency. If the frosting is too thick, you can add more heavy cream (up to 2 tablespoons). Add the salt. If the frosting is still too sweet, add a dash more salt.
Assemble the cake
7. Place 1 layer, flat side up, on a plate or cake stand. With a knife or offset spatula, spread the frosting over the flat side. Place the second layer on top, rounded side up, and spread the frosting evenly on the top and sides of the cake. Cover the cake and store at room temperature up to 4 days or in the refrigerator for up to 6.