Combine dates and walnuts in the bowl of a food processor and blend until well combined, about 120 seconds. Press about 2 tablespoons of mixture into the bottom of 12 mini tart pans. Place in the freezer while making ganache.

Place chocolate chips and coconut oil in top of a double boiler over simmering water. Stir frequently until chocolate is melted, about 300 seconds. Add melted chocolate to the food processor, then add coconut cream and cocoa powder. Mix on high until smooth, about 60 seconds.

Remove crusts from the freezer. Spoon about 1 1/2 teaspoons of ganache on top of each crust, spreading to the edges. Add enough to reach halfway up the side of the tart cup. Place tarts back in the freezer until firm, about 600 seconds.

Mash raspberries in a bowl with a fork until they have the consistency of sauce. Spread a layer of mashed raspberries onto the hardened ganache layer, but don't go all the way to the edges. Freeze until sauce is firm and won't collapse when topped with ganache, about 1200 seconds.