Preheat oven to 350 degrees Fahrenheit. Butter and flour an 8×8 inch pan.
In a stand mixer, mix the melted butter and brown sugar. Add egg and vanilla extract and mix.
In a separate bowl, mix flour, baking soda, baking powder and salt. Slowly pour the dry ingredients into the stand mixer. Scrape the sides. Mix until the mixture is smooth.
Bake for 25-30 minutes. Use a toothpick to test the center of the brownies. If it comes out clean, it’s ready to take out.