Step 1

Preheat the oven to 425°F. Spray a rimmed 13 × 18-inch sheet pan with cooking spray (this will keep the parchment in place).

Step 2

Cut a piece of parchment paper to cover the bottom completely. Place on the sheet pan and spray more oil on the parchment and around the sides of the sheet pan.

Step 3

In a medium bowl, whisk together the flours, sugar, baking powder, baking soda, and salt. In another medium bowl, whisk together the butter, buttermilk, eggs, lemon juice and zest, vanilla, and 1⁄4 cup water until thoroughly combined.

Step 4

Add the wet ingredients to the dry ingredients and whisk until just combined.

Step 5

Do not overmix (or worry if there are some lumps).Gently fold in the blueberries with a spatula.

Step 6

Pour the batter into the prepared sheet pan. Spread evenly with a spatula, then tap the sheet pan on the counter a few times to settle the batter.

Step 7

Bake, rotating the pan halfway through, until golden and set, about 15 minutes.

Step 8

Let cool for 5 minutes in the pan.

Step 9

Place a large cutting board over the top of the pan and flip the pancake onto the cutting board.

Step 10

Cut into 16 squares. Add toppings as desired and serve.