Combine flour and sugar in a medium bowl. Using a pastry blender or 2 knives, cut butter into dry ingredients until mixture resembles coarse meal. Knead until a soft dough forms. Shape ½ tablespoonfuls of dough into balls. Press balls of dough into bottoms and sides of greased mini muffin pans.
Preheat oven to 350º.
In a medium bowl, whisk sweetened condensed milk and egg. In a small bowl, combine water and coffee; stir until coffee dissolves. Add coffee mixture, melted chocolate chips, flour, vanilla and baking powder to milk mixture; beat with an electric mixer until smooth. Stir in 1 cup cashews. Spoon about 1 tablespoon filling into each pastry. Sprinkle remaining cashews evenly over filling. Bake 25-30 min or until set in center. Cool in pans 10 min. Transfer to a wire rack to cool completely. Store in airtight container.