Sift the flour and salt into a bowl. Cut in butter with a pastry blender. Add buttermilk; mix well and knead. Roll out dough 1/4-inch thick on a lightly floured surface. Cut with a round cookie cutter. Mash bananas; add coconut and mix well. Place a spoonful of this mixture in the center of each round of dough. Fold over and seal the edges, using a little water. Heat deep fat to 350 degrees and drop pastries into it carefully. Fry until golden brown. Drain well. Serve hot or cold. If desired, the pastries may be baked on a but- tered baking sheet in a 400-degree oven for 20 minutes. Yield: 6 servings.