• Preheat oven to 350 F. Line three, 8-inch round cake pans with parchment paper; or use two, 9-inch cake pans. Spray the sides with a baking spray.

Banana Walnut Cake

• In a large mixing bowl, combine the eggs, buttermilk, Baileys Irish Cream, oil, vanilla, mashed ripe bananas and sugar. Mix the ingredients together on medium-high speed for 2-3 minutes, until the eggs are well beaten.
• In a separate bowl, combine all the dry ingredients: flour, baking soda, baking powder and salt. Sift the dry ingredients into the cake batter, then mix for about 1 minute on slow speed until the flour is well incorporated. Fold in the chopped walnuts.
• Divide the prepared cake batter between the prepared pans. Bake in the preheated oven for approximately 25 minutes (30 minutes for 9-inch), or until the cakes are golden brown and a toothpick inserted into the center comes out clean. Allow the cake layers to cool in the pan for about 10 minutes, then transfer onto a wire rack to cool completely. Once the layers are completely cooled, use a serrated knife to level off the tops.

Caramel Toffee Sauce

• In a medium saucepan, combine the sugar and water. Cook the sugar over medium heat for 15 to 20 minutes, until the sugar caramelizes into a rich, amber color. Do not stir the syrup while cooking, as this will cause crystals to form on the sides of the pan. Once the syrup caramelizes, add the butter and whisk until melted. Add the heavy cream and mix again; the sauce will foam and froth. Remove the sauce from heat and add the salt and vanilla extract. Allow the caramel to cool and thicken for 2-3 hours.

Cream Cheese Icing

• Soften the cream cheese and butter at room temperature. Place the butter into a stand mixer bowl and use a whisk attachment to whip the butter. Whisk on high speed for about 5 to 6 minutes, scraping down the sides of the mixing bowl. Add the softened cream cheese next and whisk again for 2 to 3 minutes, scraping down the sides of the mixing bowl often, until the mixture is uniform and smooth.
• Add the vanilla and powdered sugar. Whisk on low speed first until the sugar is incorporated, then turn the speed up and whisk on high for 2 to 3 minutes, until the icing is light and fluffy.

Layered Banoffee Cake Assembly

• Assemble the cake only once the cake layers have cooled completely. Spread a generous about of caramel sauce onto each cake layer with an offset icing knife. Follow the caramel sauce with a generous amount of cream cheese frosting. Add a layer of sliced banana on top of the cream cheese frosting. For the the last layer, spread the top with caramel sauce, then invert onto the cake. This way, the caramel is sealed inside.
• Frost the outside of the cake with a thin, crumb-coat layer of frosting, then refrigerate for 15 to 20 minutes to chill. Then frost the outside of the cake with a generous layer of frosting, using a decorative icing comb to smooth the sides. Garnish the cake with more bananas, caramel sauce and chopped walnuts. Refrigerate the cake for at least an hour before serving; the cake will be very soft and harder to cut if not refrigerated.