Preheat your oven to 350°F (175°C). Grease and flour three 8-inch round cake pans or two 9-inch round pans, then line the bottoms with parchment circles to prevent sticking.

Spread the chopped pecans on a baking sheet and toast in the preheated oven for 5–7 minutes, just until fragrant. Remove from the oven and let cool completely before adding to the batter.

In a large bowl, whisk together the flour, granulated sugar, baking soda, ground cinnamon, ground nutmeg (if using), and salt until evenly combined and free of lumps.

In a separate medium bowl, whisk the eggs, oil, and vanilla until smooth. Stir in the mashed bananas and the entire can of crushed pineapple with its juice. The mixture will be loose and chunky.

Pour the wet mixture into the bowl with the dry ingredients. Gently stir with a spatula or wooden spoon just until you no longer see dry streaks of flour. Fold in the cooled toasted pecans. Do not overmix; a few small streaks of flour are okay.

Divide the batter evenly among the prepared cake pans. Use a spatula to smooth the tops so the layers bake evenly. A kitchen scale can help ensure the layers are the same thickness.

Bake the cakes until the tops are deep golden and spring back lightly when touched, and a toothpick inserted into the center comes out with a few moist crumbs but no wet batter. For three 8-inch pans, bake 25–30 minutes; for two 9-inch pans, bake 28–32 minutes. Remove any pans that finish earlier and let the others continue baking as needed.

Let the cakes cool in their pans on wire racks for 10–15 minutes. Run a knife around the edges, then carefully turn the layers out onto the racks. Peel off the parchment and allow the cakes to cool completely before frosting.

In a large bowl or the bowl of a stand mixer, beat the softened cream cheese and butter together on medium speed until smooth and creamy, about 2–3 minutes. Gradually add 4 cups of the sifted powdered sugar, mixing on low until incorporated, then on medium until light and fluffy. Beat in the vanilla and a pinch of salt. If the frosting is too thick, add heavy cream or milk 1 tablespoon at a time until spreadable; if too thin, add more powdered sugar a few tablespoons at a time.

Place one cooled cake layer on a serving plate or cake stand. Spread about 3/4 to 1 cup of cream cheese frosting evenly over the top. Add the second layer and repeat with more frosting. Place the final layer on top and use the remaining frosting to cover the top and sides of the cake, either fully or in a semi-naked style.

Garnish the frosted cake with extra chopped pecans, banana slices, pineapple tidbits, and/or a light sprinkle of cinnamon, if desired. If your kitchen is warm, refrigerate the cake for 20–30 minutes to help the frosting set before slicing.

Slice and serve at cool room temperature. For food safety, do not leave the frosted cake out for more than 4–6 hours. Store leftovers covered in the refrigerator for up to 4–5 days, bringing slices to room temperature for 20–30 minutes before serving.