Preheat oven to 400°F and butter a standard baking sheet (mine measures 18x13)
In a small bowl, whisk together butter, milk, eggs and vanilla.
In a larger mixing bowl, whisk together the flour, sugar, baking powder, and salt.
Add the wet ingredients to the dry ingredients and mix until everything is thoroughly combined. Don't worry if your batter looks lumpy. Pour the batter into the prepared baking sheet, and spread it out in an even layer.Allow to rest for 2 minutes.
Bake for about 20 minutes. It should be puffed up and golden, but won't brown too much on the top.
Remove from the oven, allow to cool slightly before cutting into squares and serving with butter, maple syrup or any other toppings you like!