Preheat oven to 350°F (175°C). Grease and flour three 8-inch round cake pans, then line the bottoms with parchment paper.

In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt. Set aside.

In a large mixing bowl, using an electric mixer, cream the softened butter and granulated sugar until light and fluffy, about 3-5 minutes.

Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.

Gradually add the dry ingredients to the wet ingredients, alternating with the room temperature coconut milk, beginning and ending with the dry ingredients. Mix until just combined; do not overmix.

Gently fold in the shredded unsweetened coconut.

Divide the batter evenly among the three prepared cake pans.

Bake for 25-30 minutes, or until a wooden skewer inserted into the center of a cake comes out clean.

Cool the cakes in their pans for 10 minutes, then invert them onto a wire rack to cool completely.

In a medium saucepan, combine the diced mangoes, granulated sugar, and fresh lime juice. Cook over medium heat, stirring occasionally, until the mangoes soften and release their juices, about 5-7 minutes.

In a small bowl, whisk the cornstarch with water until smooth. Stir this slurry into the mango mixture in the saucepan.

Bring the mixture to a gentle simmer, stirring constantly, until it thickens, about 1-2 minutes.

Remove from heat and let cool completely. For a chunkier filling, mash slightly with a fork or potato masher. For a smoother filling, blend briefly with an immersion blender or in a food processor.

In a large mixing bowl, using an electric mixer, beat the softened cream cheese and softened unsalted butter until smooth and creamy, about 2-3 minutes.

Gradually add the sifted powdered sugar, beating until well combined and smooth.

Add the vanilla extract, canned coconut milk, and a pinch of salt. Beat on medium-high speed until the frosting is light and fluffy, about 3-5 minutes. Be careful not to overbeat, as it can thin the frosting.

Once the cake layers are completely cool, place one cake layer on your serving plate or cake stand.

Spread about 1/3 of the cooled mango filling evenly over the first cake layer, leaving a small border.

Spread a thin layer (about 1/4 cup) of coconut cream cheese frosting over the mango filling.

Carefully place the second cake layer on top. Repeat with another 1/3 of the mango filling and a thin layer of frosting.

Top with the third cake layer.

Frost the entire cake with the remaining coconut cream cheese frosting, spreading it evenly over the top and sides.

Garnish with fresh mango slices and toasted shredded coconut, if desired, before serving.

For best results and easier slicing, chill the assembled cake in the refrigerator for at least 30 minutes to allow the frosting to set.