Combine the flour, baking powder and salt in a medium bowl and whisk to combine. Melt the coconut oil and set aside
Place the sugar, milk and the egg and whisk until the sugar is dissolved. Add the melted coconut oil (which should be cooled but still liquid) to the liquid ingredients in a steady stream and whisk constantly while adding it.
Add the dry ingredients and use a spatula to fold the ingredients until no bits of flour remain. The batter will be a little lumpy, but that is okay.
Spoon the batter into an 18-inch pastry bag. Twist the top to close it and cut an 1/2-inch opening in the other end. Pipe the batter into the 6 doughnut wells of the doughnut pan.
Bake the doughnuts for 10-12 minutes. Rotating the pan halfway through the baking. The doughnuts are done when the you press them with your finger, and they spring back. Turn the doughnuts out onto a wire rack to cool completely.
If doubling the recipe repeat the baking steps with the remaining batter, allowing the pan to cool completely and spraying with nonstick spray in between batches.
While the doughnuts are cooling combine the powdered sugar, pineapple juice and coconut milk and stir together until no powdered sugar lumps remain.
Dip the doughnuts into the glaze and swirl to coat the tops and halfway down the sides. Place on a rack or parchment paper. Sprinkle with toasted coconut.