Preheat your oven to 400º F (200º C) to ensure it's at the right temperature once the batter is ready. If desired, line a muffin tin with paper liners or lightly grease it to prevent the muffins from sticking.

In a large bowl, whisk together the all-purpose flour, 3/4 cup granulated sugar, baking powder, and salt until well combined. This helps evenly distribute the leaveners and sugar throughout the flour.

In a measuring cup that holds at least 1 cup, add the vegetable oil and large egg. Then, pour in enough milk to reach the 1-cup line (this should be about 1/3 to 1/2 cup milk). Add the vanilla extract, and whisk the mixture until smooth and well combined. I find that mixing the liquids together separately makes the muffin texture more even.

Pour the liquid mixture from Step 3 into the bowl with the dry ingredients from Step 2. Use a fork to gently combine everything until just mixed. The batter will be quite thick—be careful not to over-mix, as this can make the muffins tough.

Add the blueberries to the muffin batter. Using a spatula or spoon, gently fold them in so they are evenly distributed. If you're using frozen blueberries, there's no need to thaw them. I like to dust fresh blueberries with a little flour to help prevent them from sinking, but it's optional.

Divide the batter evenly among the muffin cups, filling each about halfway. Sprinkle a little of the reserved 1 tablespoon granulated sugar on top of each muffin for a sweet, crunchy finish.

Place the muffin tin in the preheated oven and bake for 15 to 20 minutes, or until a toothpick inserted into the center of a muffin comes out clean. Let the muffins cool in the tin for a few minutes, then transfer them to a wire rack to cool completely. I like to enjoy one while it's still a bit warm!