Preheat your oven to 425 degrees F. Line 6 cups of a jumbo muffin tin with jumbo muffin liners or spray with baking spray. Set aside.
In a medium mixing bowl, stir together the flour, baking powder, and salt. Set aside.
In a large mixing bowl, whisk together the melted butter, granulated sugar, and brown sugar until combined. Whisk in the eggs and vanilla until smooth.
Add half of the flour mixture to the wet ingredients and whisk it in until smooth. Add half of the buttermilk and whisk until smooth. Repeat with the remaining flour mixture and buttermilk until combined. Fold in the chocolate chips with a rubber spatula.
Divide the muffin batter evenly among the prepared muffin tin cups. Add more chocolate chips on top for a pretty presentation. Sprinkle the decorator’s sugar on top of each muffin, if using.
Bake the muffins for 5 minutes. Then reduce the heat to 350 degrees F and continue to bake for 25-30 minutes, until a toothpick inserted into the center comes out clean. The muffins will have a nice domed top and be golden brown.
Remove from the oven and let cool in the pan for 10 minutes. Then take them out to cool completely on a wire rack.
Notes
Instead of buttermilk, you can mix together 1/4 cup of milk and 1/4 cup of sour cream or swap in 1/2 cup of plain Greek yogurt as a substitute.
This recipe will make 12 standard-sized muffins. Bake at 425 degrees F for 5 minutes. Then reduce heat to 350 degrees F and continue to bake for an additional 13-15 minutes until a toothpick inserted into the center comes out clean.
Store at room temperature in an airtight container for up to 5 days, or freeze for up to 3 months.