Add the walnuts to a food processor and blend until finely ground, with a texture similar to coarse flour.
Add the pitted dates, dried apricots, cocoa powder, and vanilla extract. Blend again until you have a thick, sticky dough.
Line a small 5½ × 8-inch baking pan with parchment paper. Transfer the mixture to the pan and press it down firmly and evenly using the back of a spoon.
Spread the peanut butter evenly over the top of the brownie.
Sprinkle with the dark chocolate chips, then refrigerate for 30 minutes before serving.
