In a large bowl, sift together the flour, baking powder, salt, and sugar. Make a well in the middle and pour in the milk, egg, butter, and vanilla extract (if using it to add flavor). Break up the egg first with a fork and incorporate it with the liquid. Then, mix in the flour, working from the outside of the bowl in, until just combined and mostly smooth.
Step 2
Add the blueberries to the batter, and using a spatula, gently fold them into the batter just enough to coat all of them with batter.
Step 3
Heat a non-stick griddle or large pan over medium heat, and once hot, grease it. Immediately, pour ¼ cup of pancake batter onto the greased pan, making sure each pancake has about the same amount of berries. The batter is thick, so using the back of the scoop to spread it out as needed makes it easier.
Step 4
Cook the pancakes for about 2 minutes, until the edges appear defined and bubbles form on the surface. Flip the pancakes over and cook for another minute on the other side. Avoid pressing down on the pancake after flipping; this will smoosh the berries and place them closer to the heat, and can burn them. It yields denser pancakes and causes the batter to ooze out on the sides, leaving you with uncooked batter around the edges.
Step 5
Remove the pancakes from the pan onto a plate and keep them warm while you cook the remaining batter. Serve them warm with your favorite syrup and toppings.