Preheat your oven to 350°F (175°C). This ensures an even bake and helps the pancake rise properly.

Line a half sheet pan (about 18x13 inches) with parchment paper, or grease it generously with butter or nonstick spray. This prevents sticking and makes for easier cleanup.

In a large mixing bowl, whisk together the pancake mix and baking powder. Stir for about 15 seconds to evenly distribute the leavening.

Pour in the milk, crack in the eggs, and add the oil and vanilla extract. Stir the mixture together until just combined, about 1 minute. The batter should be mostly smooth with a few small lumps—don’t overmix, or your pancake may turn out tough.

Carefully pour the batter into the prepared sheet pan. Use a spatula to spread it evenly into all the corners for a uniform bake.

Place the pan in the center of the oven and bake for 10 to 15 minutes, or until the top is lightly golden and a toothpick inserted in the center comes out clean. Bake time can vary slightly depending on your oven.

Let the pancake cool for a minute or two, then slice into squares or rectangles. Serve warm with your favorite syrup, a dusting of powdered sugar, or fresh fruit.