Preheat the oven to 400 degrees F. Line 12 muffin cups with paper liners or spray the wells of the pan with non-stick cooking spray.
In a large bowl, whisk together flour, sugars, baking powder, and salt. Set aside.
In medium bowl, whisk together melted butter, eggs, milk, and vanilla, mixing until well combined.
Make a well in the center of the dry ingredients and pour the liquid ingredients into the well. Stir until ingredients are just combined - do not over mix the batter. Fold in the chocolate chips.
Evenly divide the batter into the prepared muffin pan wells. Bake for 17-20 minutes or until a toothpick inserted into the center of a muffin comes out clean.
Remove muffins to a wire rack and cool for at least 5 minutes. Serve warm or at room temperature.
Notes
These muffins were best served the day they are made; however, leftovers can be stored in an airtight container at room temperature for up to two days. I recommend warming them in the microwave for about 30 seconds before serving. Wrapped airtight, they can be frozen for up to two months.