Preheat your oven to 350°F (180°C) for a standard oven or 320°F (160°C) for a fan-forced one. Lightly grease your 8-inch round cake pan and line it with parchment paper. 

Stir together the flour, leavening agents, spices, salt, granulated and brown sugar, and pecans in a spacious bowl. Stir everything together until evenly combined, laying a flavorful foundation for your cake.

Create a space in the center of the dry mix, then add in the mashed bananas, crushed pineapple, oil, eggs, and a splash of vanilla. 

Gently fold everything together with a spatula until just combined, don’t overmix. The batter will be thick and slightly lumpy, ready to bake into something amazing.

Fill the cake pan with the batter, using a spatula to level the top. 

Bake for 60 minutes, or until a skewer or toothpick inserted into the center comes out clean or with a few crumbs. 

Once baked, let your cake cool in the pan for 10 minutes, then transfer it onto a cooling rack. 

While the cake cools, prepare the pecan cookie crumbs. Stir the chopped pecans, flour, sugar, cornstarch, and a dash of salt together in a mixing bowl. 

Add melted butter and mix until it forms a crumbly, wet sand texture. 

Spread this mixture onto a parchment-lined baking tray and bake at 350°F (180°C) for 10 minutes or until golden brown. Let it cool to create a crunchy topping.

For the frosting, beat softened butter, cream cheese, and vanilla extract in a large bowl until smooth and creamy.

Gradually add powdered sugar, one cup at a time, until the frosting is fluffy and perfectly sweet.

Let the cake cool completely, then blanket it with a rich, even coat of frosting. Sprinkle the pecan cookie crumbs for an extra layer of crunch and flavor. 

Slice, serve, and enjoy your show stopping Hummingbird Cake!