Preheat oven to 425°F (220°C). Brush a 13x9-inch rimmed baking sheet with1 tablespoon (14 grams) melted butter.
In a large bowl, whisk together flour, sugar, baking powder, baking soda, salt, and vanilla.
In a medium bowl, whisk together buttermilk, ¼ cup (57 grams) melted butter, and eggs. Stir buttermilk mixture into flour mixture just until combined. (Batter will not be smooth.) Spread batter into prepared pan.
Bake until edges are golden brown, about 8 minutes. Increase oven temperature to broil. Brush top of pancake with remaining 1 tablespoon (14 grams) melted butter. Broil until golden and edges are crisp, about3 minutes. Serve warm with softened butter and maple syrup.