• Banana Cake Layers
• Preheat oven to 350 degrees, grease and flour three 8x2 inch round pans. You could use two 9 inch pans it you do not have 8 inch pans.
• In a medium bowl, whisk the flour, baking powder, baking soda and salt for 30 seconds, set aside.
• In another bowl, add the buttermilk, vanilla and mashed bananas.  Blend and set aside.
• In the bowl of your mixer, add the slightly softened butter and mix at medium speed until smooth. 
• Gradually add the sugar and continue to mix on medium speed for 3 to 5 minutes until lightened in color and fluffy. 
• Add the eggs one at a time mixing until the yellow of the yolk disappears.
• With the mixer on low speed, alternately add the flour mixture and buttermilk mixture, beginning and ending with the dry ingredients (3 additions of dry ingredients and 2 of liquid.  Mix just until well blended- be careful not to over-mix.
• Pour batter into prepared pans and bake for 25 to 30 minutes.  Cake is done with a toothpick comes out clean or with just a few crumbs attached.  
• Cool in pans 5 to 10 minutes on a cooling rack before turning out.

Banana Pastry Cream

• In a medium size bowl, whisk the egg yolks and set aside.   In a medium size saucepan, combine the sugar, cornstarch and salt, blend together.  Gradually stir in the 2 cups of milk.  Cook over medium heat, stirring constantly to dissolve the sugar. 
• Bring the mixture to a simmer.  Remove the saucepan from the heat.  Spoon ¼ to ½ cup of the hot mixture into the bowl holding the egg yolks, stir constantly to temper the eggs. (You are tempering the eggs so you will not have tiny pieces of scrambled egg when you pour them into the simmering saucepan).  
• Pour the egg mixture into the saucepan, whisking constantly as it simmers until the mixture thickens, this could take 3 to 4 minutes. When thickened, remove from the heat and add the vanilla extract and banana extract. The filling will thicken even more as it cools. 
• Pour into a heat proof bowl to cool, for faster cooling use a 7x11 baking dish. Immediately cover with plastic wrap, pressing wrap against the filling to prevent a skin from forming.  Refrigerate until the cold before using. If you don't need it right away it can be refrigerated for 3 days, possibly longer.

Banana Cream Cheese Frosting

• Cut the butter into slices and add to the bowl of your mixer. Beat on low to medium speed until the butter is softened and smooth.
• Cut the cold cream cheese into pieces and add to the butter, beating at low to medium speed until incorporated. If you are using a hand mixer you may need to soften the cream cheese a bit more.
• Add the banana extract. Gradually add the powdered sugar beating on low speed until blended. Cover the bowl with a towel to keep down the cloud of powdered sugar.
• Increase mixing speed and beat until fluffy. Don't over beat or it will become too soft. If it becomes too soft, just refrigerate a short while to firm it up a bit.
• This frosting will pipe best if used while still chilled. You can make it in advance, refrigerate and when ready to use let it soften slightly (do not microwave) and remix.
• Will frost a 3 layer 8 or 9 inch cake.

Assembly of Cake

• Place the first (cooled) Banana Cake Layer on cake plate or pedestal. Pipe a dam of cream cheese frosting around the edge of the cake using a piping bag with the tip snipped away. (I piped my dam about ½ inch from the edge.) The dam will keep the filling from escaping as the layers are stacked.
• Spread the banana cream filling on top of the cake layer within the dam. Top with the second banana cake layer and repeat steps. Top with the third cake layer and fill in any gaps between the cake layers with additional frosting. (I use the bag that I used for piping the dam for this).
• Apply a thin layer of frosting all over the cake (this is a "crumb coat"). At this point I like to chill the cake in the freezer to firm everything up for about 15 minutes or so. Next, apply the second layer of frosting around the sides of the cake. I combed the frosting with a cake comb.
• Apply banana pastry cream to the top of the cake- I left room for a top border around the edge of the cake.
• Using a 1M piping tip, I piped a large shell border around the top and bottom of the cake.

Refrigeration

• This cake should be refrigerated because of the filling and frosting. Remove the cake from the refrigerator about 2-3 hours before serving for best texture and flavor.