Prepare the Muffin Tin:
Preheat the oven to 350°F (175°C).
Line a 12-cup muffin tin with paper liners or lightly grease each cup.
Mix the Dry Ingredients:
In a large bowl, whisk together the flour, baking powder, baking soda, salt, granulated sugar, and brown sugar until well combined.
Mix the Wet Ingredients:
In a separate bowl, beat the egg lightly. Add the vanilla extract, milk, and melted butter, and whisk until the mixture is smooth and well combined.
Combine Wet and Dry Ingredients:
Pour the wet ingredients into the dry ingredients and stir gently with a spatula or wooden spoon until just combined. Be careful not to overmix. It's okay if there are a few lumps!
Add Chocolate Chips:
Gently fold in the chocolate chips, ensuring they're evenly distributed throughout the batter.
Fill the Muffin Tin:
Using a spoon or ice cream scoop, divide the batter evenly among the 12 muffin cups, filling each cup about ¾ full.
Bake the Muffins:
Bake in the preheated oven for 18-22 minutes, or until a toothpick inserted into the center comes out clean (with a few crumbs) or the tops are golden brown.
Cool and Serve:
Allow the muffins to cool in the tin for 5 minutes, then transfer them to a wire rack to cool completely. Serve warm or at room temperature.