To make the tart shells, place the dates in a bowl, cover them with water and soak for 15 minutes. Once done, drain and discard the soak water.
Meanwhile, in the food processor, fitted with the “S” blade, process the walnuts, cacao powder, and salt. Pulse ingredients together several times. The nuts won’t break down to a fine powder due to the oils in the nuts, so be careful that you don’t over-process them and release too much of their oils.
Add the soaked and drained dates, and coconut butter. Process everything together until the batter sticks together when pinched.
Press the crust mixture evenly in the bottom of the prepared dessert pans. (we used four 3.5 inch Round Non-Stick Tart Pans). Do your best to make sure the crust is the same thickness throughout. Set it aside
To make the caramel sauce – combine all ingredients in a high-speed blender and process until smooth. Feel free to add more water to reach desired consistency. Place one heaping tablespoon of caramel sauce inside each tart shell. Reserve the remainder for another use*.
To make the chocolate filling, eat cacao butter, coconut milk, and agave nectar in a small saucepan over low heat until just melted and smooth. Do not let it come to a simmer or boil.
Remove from heat and whisk in the cacao powder until smooth and glossy.
Pour the filling mixture evenly between the 4 prepared tart shells.
Place tarts in the refrigerator to chill for at least 1 hour or overnight, or until firm. If you didn't heat the filling too much, your chill time will be significantly reduced.
Serve chilled. If desired, you can garnish each tart with cacao nibs, fresh berries and mint leaves.