Combine the flour and the baking powder in your food processor or a large bowl.
Add the dry cottage cheese and the finely cubed butter.
Dump it out onto the counter and squeeze into a flat rectangular disk, wrap in cling film and refrigerate while you prepare your fruit.
Mix together the rhubarb, sugar and tapioca.
Once you have the dough chilled, roll out a third at a time onto a floured counter top. Roll it as thin as for pie dough.
Roll it into a rectangle approximately 10 X 13. Cut the edges to make it straight leaving you with a 9 X 12 inch rectangle.
Cut into 3 inch squares. To make the perishky, put a heaping teaspoon of rhubarb onto the square and fold together the opposite corners and pinch together.
Arrange on a cookie sheet lined with parchment paper.
Bake at 350F for about 20 minutes for the perishky and about 30 minutes for a small tart.
