In a small bowl, combine pineapple, 2 tablespoons melted butter and brown sugar. Evenly spread mixture in the bottom of the bundt pan, set aside.
In a medium bowl, sift flour, cornstarch, baking powder and salt together. Set aside.
In a large bowl, beat butter and sugar until fluffy. Add the eggs one at a time until well mixed. Add vanilla extract and coconut extract.
Mix flour mixture into the batter alternating with the coconut milk. Gently fold in shredded coconut.
Transfer batter to the prepared bundt pan and bake until cooked through and the top is golden brown, about 1 hour and ten minutes.
Cool in cake pan for about 15 minutes then invert onto a cake plate. Serve warm or store in an airtight container until ready to serve.
Notes
Storage: You can store this cake on the counter for 2 - 3 days, or in the refrigerator for a bit longer than that. Keep in mind that it needs to be stored in an airtight container to prevent it from going stale. A cake stand or large, airtight cake container is your best bet.