Preheat the oven to 350 degrees F. Line a cupcake or muffin pan with 24 regular-size cupcake liners.
Measure all the ingredients accurately. Bring all the ingredients to room temperature. Place the butter in the mixing bowl. With the paddle attachment, beat the butter slowly until it is smooth and creamy. Add the brown sugar; cream the mixture at moderate speed until the mixture is light and fluffy, 8 to 10 minutes.
Add the eggs one at a time. After each addition, beat until the eggs are incorporated before adding more. After the eggs are fully incorporated, mix until light and fluffy, about 5 minutes.
Meanwhile, sift the cake flour, baking powder, salt, baking soda and nutmeg together. Be sure to scrape down the sides of the bowl to ensure even mixing. Then add one-quarter of the sifted dry ingredients to the butter mixture. Mix just until blended. Mix the milk and banana puree. Add approximately one-third of the liquids. Mix just until blended in. Repeat until all ingredients are incorporated.
Fill the cupcake liners half full with batter and bake until golden and baked through, about 35 minutes. Cool the cupcakes completely.
To assemble: Cut the center out of each cupcake and fill with the French Banana Buttercream. Dip the top of the cupcake in the Chocolate Ganache. Generously frost the top of each cupcake with the Italian Meringue Buttercream Frosting.
French Banana Buttercream:
Combine the sugar and 1/4 cup water in a saucepan. Dissolve the sugar. Boil until it reaches 240 degrees F.
While the syrup is boiling, bet the yolks with an electric mixer with a wire whip until thick and light.
When the syrup reaches temperature, pour it very slowly into the beaten yolks while whipping constantly. Continue to beat until the mixture is completely cool and the yolks are very thick and light.
Whip in the butter a little at a time, adding it just as fast as it's absorbed by the mixture.
Beat in the vanilla and banana puree. If the icing is too soft, refrigerate until it is firm enough to spread.
Put the chocolate chips in a heatproof bowl. In a saucepan, heat the heavy cream to a simmer. Once a simmer is reached, pour over the chocolate chips. Using a whisk, whip until smooth and creamy.
Italian Meringue Buttercream Frosting:
Combine 1 cup sugar and 1/2 cup water in a saucepan. Boil to reach 230 degrees F. Leave it alone. Cook over medium heat.
While the syrup is boiling, using a whip attachment, start beating the egg whites and cream of tartar in a mixing bowl. Once peaks begin to form, add the remaining 1/4 cup sugar to make the peaks stiff.
When the syrup reaches temperature, slowly pour it into the beaten egg whites while whipping constantly with the mixer on the lowest speed. Beat on high until cool, about 5 minutes.
Turn down to medium-low speed and add the butter on the sides and scrape. Turn to high and beat until you have a smooth texture. Add the vanilla and chocolate ganache.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.