Begin by preheating your oven to 400°F (200°C). Prepare a 12-cup muffin tin by either greasing it or lining the cups with paper liners.
In a small bowl, thoroughly whisk together the milk, vegetable oil, and egg until smooth and well combined. In a separate large mixing bowl, whisk the flour, ½ cup sugar, baking powder, and salt. Create a well in the center of the dry ingredients, then pour in the milk mixture. Stir gently until just combined, taking care not to overmix. Gently fold in the mini chocolate chips.
Spoon the batter into the prepared muffin cups, ensuring each is filled about ⅔ full. In a small bowl, mix together the remaining white sugar and brown sugar, then sprinkle this mixture evenly over the tops of the muffin batter.
Bake the muffins in the preheated oven for 18 to 20 minutes, or until the tops spring back when lightly pressed. Allow them to cool briefly in the tin before transferring them to a wire rack to cool completely. Enjoy them warm or at room temperature.