Preheat oven to 375℉ (190℃)
Line muffin cups with paper or foil liners
Stir together flour, granulated sugar, baking powder, and salt in a large mixing bowl
In a measuring cup at least 2 cups (473 ml) size, add oil and large egg. Add milk to fill measuring cup to 1¼ cup (296 ml) line.
Add the vanilla to the measuring cup and stir to combine well
Add wet ingredients mixture to dry ingredients and stir until just combined.
Gently fold in the blueberries. Do not overmix the batter or muffins will come out rubbery.
Sprinkle tops with coarse sugar
Place muffins in oven on rack in middle and bake for approximately 20 minutes or until tops are not shiny wet and an inserted toothpick in the middle of the muffins does not come out with batter, only crumbs or clean
When baked, take muffins out of oven and let cool until you can handle then remove muffins from tin and separate out onto a plate or platter