Tropical fruit adds a fresh twist to this traditional dessert that is halfway between a coffeecake and a crumble.
Preheat oven to 350 degrees. Butter a 2-quart baking dish. Toss pineapple, mangoes, and brown sugar together in a bowl. In a separate bowl, whisk together flour, cinnamon, salt, and baking soda.
Beat butter and granulated sugar in a mixing bowl until fluffy, about 2 minutes. Beat in vanilla. Add eggs, one at a time, beating well after each. Add flour mixture; beat until just combined. Measure out 1 cup fruit mixture; fold rest into batter.
Spread batter into prepared baking dish; sprinkle reserved fruit over the top. Bake until golden on top and a cake tester inserted in the center comes out clean, 45 to 50 minutes. Serve warm.