Preheat oven to 350 degrees and spray a muffin pan with non-stick spray. Set aside.
In a heavy-bottomed pan, over medium-low heat, melt your butter, stirring nearly constantly. The butter will melt, then foam, then clear up, turn golden, then start getting brown flakes and smell nutty. Once you start seeing the brown flakes, remove the pan from the heat and continue to stir it for about a minute.
Pour the browned butter into a large mixing bowl and allow it to cool for a couple minutes.
Add the egg, sugars, and vanilla and whisk to combine until smooth.
Add in the flour, baking soda, and salt, and stir until just combined.
Fold in the chocolate chips.
Using a cookie scoop (or not, but it makes life easier), fill each of the 12 muffin wells evenly.
Bake for 9-11 minutes or until the tops have just set and start to golden. Don’t over bake them because they will firm up as they cool.
Use restraint and let the cups cool in the pan for 20 minutes before removing them. I used a silicone pan so they’re easy to pop out.