Prep the oven and pan: Heat the oven to 350°F (175°C). Lightly butter a 9-inch square baking dish or similar 2-quart dish.

Mix the mango filling: In a large bowl, toss diced mango with sugar, lime juice, lime zest, cornstarch, vanilla, and a pinch of salt. Stir until the fruit is evenly coated and glossy. Spread the mixture into the prepared baking dish.

Make the crumble: In another bowl, combine flour, oats, shredded coconut, brown sugar, ground ginger, and salt. Add the cold butter cubes.

Cut in the butter: Use your fingertips or a pastry cutter to work the butter into the dry ingredients until it forms moist, pea-sized clumps. You want a mix of large and small crumbles. If it looks dry, squeeze a handful to check—it should hold together, not feel sandy.

Top the mango: Sprinkle the crumble evenly over the fruit. For extra texture, scatter coconut flakes over the top.

Bake: Place the dish on a rimmed baking sheet to catch any bubbling. Bake for 35–45 minutes, until the topping is golden and the filling is bubbling around the edges.

Rest: Let the crumble cool at least 15 minutes. This helps the juices thicken so the filling is jammy, not runny.

Serve: Spoon warm crumble into bowls. Add a scoop of ice cream or a dollop of yogurt. The creamy coolness against the warm, tangy-sweet mango is wonderful.