Preheat oven to 450F.
Start by the melted butter in a 9" square baking pan, set aside.
In a large bowl, whisk the flours, salt, baking powder and sugar together in a bowl.
Add the buttermilk and stir until well combined, the dough should be very sticky. The batter will be wetter/runnier than a typical biscuit batter.
Gently fold in the blueberries.
Spoon the batter into the prepared pan with the butter. Spread the batter into the edges as best as you can.
Use a spatula to cut the dough into 9 squares.
Bake for 30-35 minutes or until golden brown. Around the 25 minute mark, if the top is very brown, cover with foil to prevent burning.
Serve warm with honey if desired.
