Center a rack in the oven and preheat to 350 (F). Prepare two 8-inch cake pans by spraying the bottom and sides with cooking spray and lining with a parchment paper circle. Spray the parchment paper circles as well and set aside.
In a medium bowl, whisk together 3 cups all-purpose flour, 2 teaspoons ground cinnamon, 2 teaspoons baking powder, 1 teaspoon baking soda, and 1/2 teaspoon kosher salt until well combined. Set aside.
3/4 cup tightly packed dark brown sugar, and 3/4 cup canola oil. Beat on medium speed for 2 minutes, before turning the mixer to its slowest setting and adding 4 large eggs, one at a time, only adding the next egg when the previous one is fully incorporated. Add 2 teaspoons pure vanilla extract and continue mixing until incorporated.
Stop the mixer and scrape down the sides of the bowl with a rubber spatula. Turn on the mixer back to its slowest setting, add the flour mixture (from the 2nd step) in 2 batches. Add 1 cup mashed bananas and 1 cup crushed pineapple and continue mixing until just incorporated. Turn off the mixer and sprinkle 1 cup roughly chopped pecans over the batter and use a rubber spatula to fold the nuts into the batter, making sure to scrape down the sides and bottom of the bowl. Divide the batter evenly between the prepared pans. Bake in the preheated oven for 30 to 40 minutes, or until a toothpick inserted into the center of the cakes comes out clean and the top of each cake bounces back when gently poked. Transfer to a wire rack to cool completely.