Preheat oven to 425 F and position an oven rack in the centre. Line a large baking sheet with parchment paper or a silicone mat.

Place the flour, lemon zest, baking powder, baking soda and salt in a large bowl of a food processor and mix for 10 seconds to blend. Add the cold butter pieces and pulse until butter is cut into case pieces. Add in buttermilk and bananas and mix until dough comes together in large think clumps. You can add more flour here if its still too sticky and wet. Mix in blueberries with a spatula. Flour your work surface and turn out dough. Gently need the clumps of dough not to burst the blueberries, until form a soft dough. If the dough still seems sticky, you can continue to dust with flour lightly.

Pat the dough down to form a round circle 7 inches in diameter and 1 inch thick. Using a flour dusted knife, cut into 8 equal size triangles. Gently transfer to baking sheet and brush the top of each with the beaten egg. Sprinkle top with sugar and bake for 15-17 minutes until firm to touch and golden. Transfer to cooling wrack and let stand for a few minutes before serving with smoked honey butter.

To make honey butter, which butter until creamy and swirl in honey.