step 4: make the batter.
pour the butter and the milk into the hole you made in the flour. mix everything together with the electric mixer. add the egg and keep mixing. then, add the vanilla. don't mix the batter too much. a few lumps are ok. add the blueberries and use a spoon to stir. be careful not to squish the blueberries.
step 5: get ready to bake.
pour the batter into each section of the muffin tin. sprinkle the remaining sugar over each muffin.
step 6: bake it!
bake for about 16 to 20 minutes. the tops of muffins will be golden brown. check that they're done by inserting a toothpick into the middle of the muffin. if it comes out with a few (quite dry) crumbs, they're ready. let the muffins cool in the tin for a few minutes before serving.