Line an 8x8 baking pan with parchment paper.
In the bowl of a food processor, place dates, almonds, oats, salt, cocoa powder, and coconut. Pulse a few times then add melted butter. Process until "dough" comes together and almonds are in small pieces. If your mixture is not coming together, add a teaspoon of water.
Transfer mixture to prepared pan. Press into an even layer and refrigerate for at least 15 minutes.
While the base chills, prepare your dairy-free buttercream. In a medium bowl, cream your vegan butter for about 30 seconds, then add coconut milk, arrowroot starch, powdered sugar, and a couple pinches of turmeric. Use an electric mixer on medium to high speed until mixture is smooth and creamy.
Take the base layer out of the fridge and spread the buttercream on top in an even layer. Place pan back in refrigerator while you prepare the chocolate topping.
In a glass or microwave safe bowl, add your chocolate chips and vegan butter. Microwave for 30-second intervals, stirring after each, until mixture is almost completely melted. Stir until remaining chocolate chips dissolve.
Remove pan from refrigerator again and working quickly, pour melted chocolate over top and gently spread it into an even layer over buttercream.
Place pan in refrigerator and chill for at least 30 minutes. Using parchment paper, remove bar from pan and transfer to a cutting board. Use a sharp knife to cut 9 squares. Store in an airtight container in the refrigerator.