Preheat oven to 350℉. Line 8-inch square baking pan with parchment paper, leaving an overhang on all four sides of pan. Set aside. Fill a medium pot with about two inches of water. Bring to a simmer. In a large bowl, combine chocolate and butter. Set over pot of simmering water. Make sure bowl does not touch the water. Melt together ingredients.
Add granulated sugar and brown sugar to large bowl. Stir until dissolved. Remove from heat.
Whisk in ube halaya. Whisk in eggs one at a time until fully incorporated.
Stir in ube extract, vanilla extract, and coconut extract (optional).
In a small bowl, whisk together flour, baking powder, and salt. Fold flour mixture into wet ingredients.
Transfer batter to prepared baking pan. Bake for 25-30 minutes until just set and toothpick inserted in center of pan comes out clean. Cool in pan for about 20 minutes. Unmold and cool further on wire rack.
Use a sharp knife to slice completely cooled ube brownies into desired portions.