Preheat the oven to 400°F. Melt 1 tablespoon of the butter in a 9x13 inch baking pan, swirling to coat the bottom and sides completely. Set the greased pan aside.

Combine the flour, sugar, baking powder, baking soda, and salt in a large bowl, whisking to distribute evenly. Add the cold butter cubes and cut them into the flour mixture using a pastry cutter, two knives, or your fingertips until the mixture looks like coarse breadcrumbs with some pea-sized butter pieces remaining.

Add the blueberries and lemon zest to the flour-butter mixture, stirring gently to avoid crushing the berries. Pour the cold buttermilk over the mixture and fold with a spatula just until combined—the dough will be slightly shaggy and moist.

Spread the dough evenly into the prepared baking pan, smoothing it gently to reach the edges. Use a sharp knife to score the dough into 9 equal squares (3 rows by 3 columns), cutting about halfway down through the thickness.

Bake in the preheated oven for 40 to 45 minutes, until the top is deeply golden and a toothpick inserted in the center comes out clean. The surface should spring back when lightly pressed.

While the biscuits bake, stir together the melted butter, honey, pinch of salt, and vanilla extract in a small bowl until smooth and well combined.

Remove the biscuits from the oven and cool in the pan for 5 minutes. Invert the pan onto a wire rack or cutting board to release the biscuits in one piece, then carefully break them apart along the scored lines. Brush all sides of the warm biscuits generously with the honey butter glaze. Let cool for 10 minutes before serving.