Prepare the brownie mixture: using a food processor, place almonds, pecans, cocoa powder, and sea salt (if using) and pulse until fine mince (flour-like texture)
Slowly drop in the pitted dates while continuing to pulse until all dates are incorporated into the batter. If dates are wet from sail it’s okay. The mixture will be quite thick and balled up. (Cookie-dough texture)
Line a small brownie pan (9 in x 9 in) with parchment paper. Scoop out the brownie mixture and press into the pan, spreading evenly. Place aside.
For the frosting: using a food processor, add all ingredients to a food processor and blend until smooth.
Spread frosting over the brownies covering entirely (use a spatula or spoon).
Sprinkle the remaining chopped nuts over the top of the brownies.
Wrap and place in freezer for a minimum of 2 hours to firm up quickly.
Remove from freezer, slice and serve. Alternatively, these could be stored in the refrigerator.