Preheat the oven to 350°F and lightly spray a 9x13-inch baking dish with nonstick cooking spray.
Drain the pineapple in a mesh sieve or colander over a bowl so you can save the juice.
In a medium bowl, whisk together the flour, baking powder, and baking soda. Add the melted butter, sugar, eggs, and reserved pineapple juice and mix well with a hand mixer (or in a stand mixer). Fold in the drained pineapple. Pour the batter into the prepared pan and spread evenly.
In a small bowl, combine the brown sugar, pecans, and coconut flakes. Sprinkle evenly over the batter.
Bake for 30 to 35 minutes or unit the cake stars pulling away from the edges and a toothpick inserted into the center comes out clean. Serve warm.
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