Preheat the oven to 425°F (220°C). Line a muffin pan with 6 paper liners or lightly grease each cup.
In a large bowl, whisk together the flour, granulated sugar, brown sugar, baking powder, and salt.
In a separate medium bowl, whisk together the milk, oil, egg, and vanilla extract until well combined.
Pour the wet ingredients into the bowl of dry ingredients and stir with a wooden spoon or silicone spatula until just combined. Be careful not to overmix.
Fold in the chocolate chips until evenly distributed throughout the muffin batter.
Use a cookie scoop to divide the batter evenly between the 6 muffin cups. The cups will be nearly full.
Sprinkle the tops with coarse sugar for that classic bakery-style sparkle (optional but delicious!).
Bake at 425°F for 5 minutes. Then, without opening the oven door, reduce the temperature to 350°F (175°C) and bake for another 18-20 minutes, or until the tops are golden brown and a toothpick inserted into the center comes out with moist crumbs.
Let the muffins cool in the muffin pan for 5 minutes, then transfer to a wire rack to cool completely.