Line a 9-inch square baking dish with parchment paper and set aside. I like to lightly spray the pan with oil, to help the parchment paper stick in place. To prepare the topping, add the pecans, dates, coconut oil, and salt to a food processor fitted with an "S" blade, and process until sticky.
Reserve 1 loose cup of this mixture for the crumble topping. Press the rest of the dough evenly into the lined baking dish, then set it aside.
In a medium bowl, prepare the chocolate filling by whisking together the cacao powder, coconut oil, and syrup until smooth. Pour the chocolate filling over the crust and smooth the top with a spatula.
Sprinkle the remaining 1 cup of crumble over the top of the chocolate layer and use your hands to gently press the topping into the chocolate filling. Place in the freezer to set for at least 2 hours.
Use the parchment paper to lift the bars out of the pan. Cut them into 16 small squares, then serve chilled. Store leftover bars in an airtight container in the fridge for up to 3 months. For a softer texture, you can also store them in the fridge for up to 2 weeks. Do not let these sit out at room temperature for too long, or they'll become too soft to pick up.