Preheat oven to 350F (175C) and lightly grease and flour the sides and bottoms of two 8" or 9" pans. I also recommend using a cut-out round of parchment paper to line the bottom to prevent sticking.
Combine butter, oil, and sugars in a large bowl and use an electric mixer (or a stand mixer) to beat together until creamy and well-combined.
Add eggs and stir to combine.
Add bananas, crushed (undrained) pineapple, and vanilla extract and stir well.
In a separate, medium-sized bowl, whisk together flour, baking soda, baking powder, cinnamon, and salt until thoroughly combined.
Using a spatula (don't use an electric mixer for this step) gradually begin to fold dry ingredients into wet. Once about half the flour mixture has been added, add the pecans and stir them in as well. Stir until completely combined, but don't over-mix the batter or you could end up with a dry cake.
Evenly divide cake batter into prepared baking pans. Transfer to center rack of 350F (175C) oven and bake for about 39 minutes if using 8" pans and about 34 minutes if using 9" pans or until a toothpick inserted in the center comes out clean or preferably with a few moist crumbs.
Allow to cool for 10 minutes in baking pan then run a knife around the inside of the pan to loosen cake and carefully invert onto a cooling rack to cool completely.
Once cooled completely, prepare cream cheese frosting.
Combine butter and cream cheese in a large bowl (or in the bowl of a stand mixer) and beat until creamy, smooth, and well-combined.
Stir in vanilla extract and salt.
Gradually, with your mixer on low speed, stir in powdered sugar until completely combined. Be sure to scrape the sides and bottom of the bowl so ingredients are evenly combined.
If needed, level cakes before decorating. Place one layer of the cake on serving platter. Top with cream cheese frosting and spread evenly. Top with second cake. Frost top and sides of cake and serve.