Preheat oven to 450˚F.
Grease an 18x13 baking sheet with cooking spray and set aside. For a taller pancake, use a 15x11 baking sheet.
In a mixing bowl, whisk together buttermilk, eggs, and vanilla.
Whisk in the slightly cooled melted butter; set aside.
In a separate mixing bowl, combine flour, sugar, baking powder, baking soda and salt; whisk until well combined. If using lemon zest, whisk that in, too.
Add the flour mixture to the buttermilk mixture and fold until thoroughly incorporated.
Transfer batter to previously prepared baking sheet and spread it out into an even layer. Top with blueberries, if using.
Bake for 15 to 18 minutes, or until pancake is puffed up, top is golden brown, and pulls from the edges of the pan.
Remove from oven and allow to cool slightly.
Cut, serve, and enjoy!