Line an 8x8 baking dish with nonstick parchment paper, leaving an inch or so overhanging the sides.

In a food processor, combine all brownie ingredients and process until it forms a sticky crumble. You don't want to over-process, or some of the oil will start to leak out and it may get chewy. You just want to be able to pinch the mixture in your fingers and it sticks. Taste mixture for more cocoa powder. I personally use 8 tablespoons total, because I like a more bitter flavor, but it's up to you!

Press brownie mixture into your lined dish and press into an even layer. To get nice edges, you can fold the parchment in and run your finger along the edge.

In a mixing bowl, whisk together all frosting ingredients. Pour over brownies in an even layer, then place in the freezer on a flat surface. Sprinkle on extra sea salt and cacao nibs, if using. Freeze for at least 30 minutes before removing and slicing into whatever sized pieces you like. I personally don't cover the dish for these 30 minutes but you can! Brownies will keep tightly sealed in the refrigerator for up to 1 week or in the freezer 2 months.