Using a stand mixer with paddle attachment or handheld mixer, beat both sugars and oil for 2-3 minutes until smooth.
1 cup (200g) granulated sugar, 1 cup (200g) lighlty packed brown sugar, 1 & 1/4 cups (300ml) vegetable oil
Add in the eggs one at a time, mixing well in between, then mix for 2 minutes until light and fluffy.
3 large eggs
Mix in the vanilla, bananas and pineapples until just combined.
2 tsp vanilla extract, 2 cups (500g) mashed very ripe bananas, 8 oz (1 can) crushed pineapples
On low speed, add the dry ingredients in thirds, beating until just combined. Fold in the pecans.
1 cup (125g) chopped pecans
Divide the batter evenly between the two prepared cake pans. Tap the pans firmly on the countertop to remove any air bubbles from the batter.
Bake for 40-50 minutes or until a toothpick inserted into the center comes out clean. Cool completely before frosting.
Frosting
Using a stand mixer with paddle attachment or handheld mixer, beat the butter, cream cheese, vanilla and salt until smooth and creamy (3-5 minutes).
1/2 cup (114g) unsalted butter, 16 oz (2 pkgs) cream cheese, 2 tsp vanilla extract, 1/4 tsp salt
Slowly add in the powdered sugar, beating until light and fluffy (5-7 minutes).
5-6 cups powdered sugar
When ready to assemble, level the tops of the cakes with a serrated knife. Place one layer cut side down on a serving plate. Spread one third of the frosting on top. Place the other layer cut side down on top and spread the remaining frosting all over the cake.
Refrigerate for 30 minutes to firm up the cake to make it easier to slice.
Notes
Leftover cake can be covered and stored in the fridge for up to 3 days.