Place the dry ingredients - flour, baking powder, salt, sugar, and lemon zest - in a bowl and whisk to combine.
Add the eggs, milk, oil, and lemon juice. Whisk until you have a smooth batter. Gently fold in the blueberries until evenly distributed.
Heat your waffle iron and grease it. I like to use cooking spray for this.
Depending on the size of your waffle iron, fill the plates with about 1½-2 scoops of batter. Close the waffle iron and bake until the waffles are golden brown. Cooking time will vary per waffle iron; mine took about 5-7 minutes.
Remove the waffles from the iron and place them on a wire rack to cool.
How to store
Store in an airtight container at room temperature for 3-4 days. Freeze for up to 3 months.