In a large bowl, add 1 ¼ cups of flour, baking powder, salt, and sugar. Make a well in the middle and pour in the milk, egg, and butter. Mix with a whisk or fork until smooth.
Before you add the blueberries, let the batter sit for 5 minutes. Add more gluten-free flour if needed (see note below).
Fold in the blueberries:
Add the blueberries to the batter, and using a spatula, gently fold them into the batter.
Cook the pancakes:
Heat a non-stick griddle or large pan over medium-high heat. Once hot, grease it with oil or butter. Immediately, pour or scoop ¼ cup of blueberry batter for each pancake. Wait until the edges are defined and bubbles form throughout to flip. Cook on the other side for one more minute. Do not press them down with a spatula. Remove them from the pan and repeat with the remaining batter.
Stack them up!
Serve the pancakes warm and top with fruit, syrup, or your favorite toppings.
Notes
All gluten-free all-purpose flour mixes vary in consistency due to the ingredient % used in the mix. Make sure your mix includes xanthan gum. If it does not have xanthan gum in it, add ¾ to 1 teaspoon to the dry ingredients to bind them in the batter. I recommend slowly adding the last ¼ cup of flour into the batter. Test with one pancake after waiting 5 minutes for the liquid to absorb, then troubleshoot if necessary.
Use the right baking powder: Since pancake batter naturally has a mild, neutral flavor, it's important to use aluminum-free baking powder. The metallic flavor will ruin the taste, especially in fluffy pancake recipes that call for 2 or more teaspoons. Trust me on this one.