Preheat oven to 350F. Line an 8-inch by 8-inch square baking pan with two rectangles of parchment paper. Squeeze one lime or two to gather 3 tablespoon of fresh juice. Zest the skin so you have about 2 tablespoon of zest to top the baked brownies.Melt the butter for 10 seconds in the microwave.
Make the brownies
Mix the dry ingredients in one bowl. Not the chocolate chips yet.
Mix the wet ingredients in another bowl.
Pour the dry ingredients into the wet bowl and use a hand-mixer to blend up smooth. Fold in the chocolate chips.
Pour the brownie batter into the lined square pan, tap until the surface is even. Bake the pan for about 25 minutes and until top cracks a bit. Remove pan from oven, let it cool to touch.
Once cool, sprinkle on lime zest, slice and eat!
Storage
Store at room temperature for three days. They freeze well for up to three months.