Preheat oven to 350°F and line a baking sheet with parchment paper or Silpat liner.

In a large bowl, mix together all-purpose flour, whole wheat flour, brown sugar, and baking powder.

Using a medium-size grater, grate frozen butter into flour mixture. Stir to incorporate butter but only so that butter is well-distributed throughout; you want the butter to stay in pieces and not blended in.

Mix in 1/4 cup coconut milk and egg, then add pineapple and shredded coconut, mixing until just incorporated throughout.

Turn dough out onto a lightly floured surface and gather together into a ball. It will be somewhat sticky, so use a little bit of flour to keep it from sticking to the work area. Pat into a large circle about 1/2 inch thick, and cut into 8 wedges.

Transfer wedges to prepared baking sheet and bake for 25 minutes, until golden brown. Let cool on a wire rack.

To make the glaze, whisk together powdered sugar, 1 tablespoon coconut milk, and reserved pineapple juice until smooth and no lumps remain. Drizzle over cooled scones. Let glaze set for at least 5 minutes before serving.

Store leftover scones in an airtight container for up to 3 days.