Step 1: Preheat your oven to 350°F (175°C). Grease and flour three 8-inch round cake pans.
Step 2: In a large bowl, whisk together the flour, 2 cups granulated sugar, baking soda, cinnamon, and salt. Set aside.
Step 3: In a separate bowl, mash the ripe bananas. Stir in the buttermilk, melted butter, eggs, and 2 teaspoons vanilla extract until well combined.
Step 4: Gradually add the wet ingredients to the dry ingredients, mixing on low speed until just combined. Fold in 1 cup of the toasted chopped pecans.
Step 5: Divide the batter evenly among the prepared pans. Bake for 25-30 minutes, or until a wooden skewer comes out clean. Cool in pans for 10 minutes, then invert onto a wire rack to cool completely.
Step 6: To make the caramel: Combine 1.5 cups granulated sugar and water in a heavy-bottomed saucepan. Cook over medium heat, stirring until sugar dissolves, then stop stirring.
Step 7: Continue cooking, swirling occasionally, until the syrup turns a deep amber color (8-12 minutes).
Step 8: Carefully pour in the warm heavy cream (it will bubble). Stir continuously until smooth. Add 4 tablespoons butter and a pinch of salt, stirring until melted. Let cool completely.
Step 9: To make the frosting: Beat softened cream cheese and 0.5 cup softened butter in a large bowl until smooth.
Step 10: Gradually add powdered sugar, then beat in 1 teaspoon vanilla extract until light and fluffy.
Step 11: To assemble: Place one cake layer on a serving plate. Spread with 1/3 of the frosting. Drizzle with cooled caramel sauce.
Step 12: Sprinkle with a portion of the remaining toasted pecans. Repeat with the second cake layer.
Step 13: Top with the third cake layer. Frost the top and sides of the entire cake with the remaining frosting.
Step 14: Drizzle remaining caramel sauce over the top, letting it drip down the sides. Garnish with the remaining toasted pecans. Chill for at least 30 minutes before serving.