1/2 cup (1 stick) unsalted butter, room temperature
1 1/2 cups all-purpose flour
1/2 teaspoon baking soda
1/2 teaspoon salt
1 cup sugar
3 large eggs
1 cup sour cream
1 can (20 ounces) pineapple chunks in juice, drained well
Preheat oven to 350 degrees F. Pour pineapple chunks into a fine mesh strainer and allow to sit and drain, at least 10 minutes. On a large rimmed baking sheet spread coconut. Bake until lightly toasted, tossing occasionally, 6 to 10 minutes.
Grease bottom and sides of a 9 x 5-inch loaf pan; dust with flour, tapping out excess. In a medium bowl, whisk together flour, baking soda, and salt; set aside.
In the bowl of a stand mixer fitted with the paddle attachment, beat butter and sugar on high speed until light and fluffy, about 3 minutes. Add eggs, one at a time, beating well after each addition. Reduce speed to low, and alternately add flour mixture in three parts and sour cream in two, beginning and ending with flour mixture. Mix just until combined.
Fold pineapple and 1 cup toasted coconut into batter. Scrape batter into prepared loaf pan and smooth surface with a rubber spatula; sprinkle with remaining 1/2 cup coconut. Bake until a toothpick inserted in center comes out clean, 65 to 70 minutes (cover pan with foil halfway through). Let cake cool in pan 15 minutes. Remove from pan, and transfer to a wire rack to cool completely.