Add the dates, cashews and salt to the bowl of a food processor. Blend on high for 1-2 minutes until the ingredients start to form a dough and pull away from the sides of the bowl. If ingredients aren't mixing well add a tablespoon of water and blend until combined.
Press dough into the bottom and sides of the mini tart pan using a rubber spatula to avoid sticking. Make sure you get an even consistency on the bottom and the sides. Repeat this process for all of the tarts
Fill each tart about 3/4 way full with greek yogurt. Top with assorted berries or fruit and serve.
Keep crusts covered in an air tight container in the refrigerator for up to 5 days. Top with greek yogurt and berries before serving.