Step 1

Getting Ready: Adjust oven rack to the middle position and preheat to 350°F (180°C). Toast pecans on a half-sheet pan until golden brown, about 10 minutes, then let cool completely. (The pecans may be toasted in advance and stored in an airtight container at room temperature for several weeks.) Meanwhile, peel, trim, and core the pineapple and measure 5 ounces (about 2/3 cup; 140g) fruit into the jar of a blender, or a tall, narrow jar if using an immersion blender. If you like, reserve the pineapple scraps to make fresh pineapple syrup. Peel banana and measure out 3 ounces fruit (about 1/3 cup; 85g) to add along with the pineapple. Blend until smooth. Use purée immediately or refrigerate up to 3 days and bring to about 70°F (21°C) before use.

Step 2

For the Cake: Combine sugar, baking powder, salt, cinnamon, cloves, baking soda, nutmeg, eggs, and vanilla in the bowl of a stand mixer fitted with the whisk attachment. Mix on low to moisten, then increase to medium and whip until thick and fluffy, about 5 minutes. Add melted butter in a steady stream, then reduce speed to low and add flour. Once smooth, add fruit purée and mix only until well combined. Fold in toasted pecans with a flexible spatula, scraping the bowl along the bottom and sides to ensure batter is well mixed throughout.

Step 3

Bake until the cake is well risen and golden brown, about 45 minutes. A toothpick inserted into the center will have a few crumbs still attached when removed, and your fingertip will leave a slight indentation in the puffy crust. Transfer to a heat-safe surface or a wire rack and cool until no trace of warmth remains, at least 90 minutes. (The time will vary depending on the cast iron's gauge and the type of cooling surface.)

Step 4

To Finish: Top the cake with about 2 cups of your favorite cream cheese frosting or buttercream, along with a scattering of toasted pecans. Enjoy immediately or leave at room temperature until ready to serve, up to 24 hours at cool room temperature. After cutting, wrap leftover slices individually and store at cool room temperature up to 2 days more.