In a large bowl, whisk the pancake mix, milk, egg, oil, & vanilla extract until smooth.
Pour pancake batter onto the prepared baking sheet & spread it in an even layer to the edges.
Bake for 12-15 minutes at 425°F (218°C) until the top of the pancake is dry & the edges start to brown.
Remove from oven & let cool for 5 minutes. Slice into squares or individual pancakes & serve warm with toppings.