01 -
Preheat oven to 450°F (230°C). Grease a 9x13-inch baking dish or line with parchment paper.
02 -
In a large mixing bowl, whisk together flour, baking powder, salt, and sugar until well combined.
03 -
Add cubed cold butter to the flour mixture. Use a pastry cutter, fork, or fingers to mix until the mixture resembles coarse crumbs.
04 -
Pour in buttermilk and gently fold until just combined. Do not overmix. Carefully fold in blueberries and lemon zest if using.
05 -
Melt 1/4 cup of unsalted butter and pour into the prepared baking dish, spreading evenly across the bottom.
06 -
Spoon the biscuit dough into the baking dish over the melted butter. The dough will float on top, creating the swim effect while baking.
07 -
Bake in the preheated oven for 15-20 minutes, or until tops are golden brown and a toothpick inserted in the center comes out clean.
08 -
Drizzle with honey if desired for added sweetness. Allow biscuits to cool for a few minutes before cutting into squares. Serve warm.