Add your flour, sugar, baking powder and salt to a medium mixing bowl and whisk to blend.
Add your eggs to a liquid measuring cup and whisk to beat them. Add the beaten eggs to your mixing bowl.
Add your milk and oil to the measuring cup and whisk to combine. Add that liquid to your mixing bowl. Whisk your batter just until combined. It should still be lumpy.
Rinse your blueberries and pat them dry with a paper towel. Gently stir in 1 cup of blueberries to your batter.
Heat an 8-inch skillet (or a pancake griddle) over a medium-high flame, until it is hot enough that a drop of water splashed on it will sizzle. Spray the pan with cooking spray.
Use a large serving spoon to pour some batter into the center of the pan, using two full spoons for each pancake. The pancakes will be about 6 inches in diameter.
Flip each pancake when bubbles form on top, and the edges appear dry. Cook the second side until it is lightly browned. Remove cooked pancakes to a platter and cover with foil to keep warm. Spray the pan with cooking spray each time before adding batter to the pan.
Serve the pancakes with butter, powdered sugar, maple syrup, and extra blueberries, if you wish. Store any leftover batter in the refrigerator for up to two days. Cooked pancakes can be frozen.