Grease cookie sheet.
In a bowl, sift together the flour, baking powder and salt.
In another large bowl, add the butter and sugar and beat until creamy. Add eggs and lemon flavoring and beat until well combined.
Add the milk and flour mixture alternately in three parts, starting with the milk.
Gently fold in the blueberries
Spoon the mixture onto the cookie sheet about 1 and ½ inches apart.
Bake for about 12-15 minutes.