1. Preheat oven to hot (425° F.).
2. Sift together the flour, salt, baking powder and sugar. Using a pastry blender, chop in the butter until well mixed. Add the milk all at once and then more if necessary to give a soft dough. Turn the dough out on a floured surface and knead about thirty times.
3. Press half the dough into a greased 8 by 8-inch pan. Brush with the two tablespoons melted butter. Press the second half of the dough into an eight-inch square and place on top. Bake until brown, about twenty minutes.
4. Slide a cookie sheet between the layers to separate them. Place the bottom layer on a serving plate, spread generously with half the marmalade and cover with half the banana slices. Cover with the remaining shortcake and spread with marmalade and banana. Top with whipped cream.