Put all ingredients, except water, in a food processor.
Process until avocado or banana is thoroughly blended with the flour.
Add water 1 tablespoon at a time, until dough just holds together.
Roll out into a large circle, about 1/4" thick, on a floured surface.
Roll dough onto rolling pin and then unroll over your pie dish.
Gently press dough into the pie dish and trim the edges.
Finish the edges by making imprints with a fork or your fingers.
Add filling and bake for 1 hour at 350 degrees.