1) In the bowl of an electric mixer, beat together the butter and cream cheese, at high speed, until they're very light and fluffy. Add the salt, sugar, flour, and baking powder, and mix to combine; the batter will be stiff. Add the extracts, and 1 egg. Beat well. Continue to add the eggs one at a time, beating well after each egg is added; the finished batter should be extremely light and fluffy.
2) Spoon the batter into a greased 9" x 5" loaf pan. Bake the cake in a preheated 325°F oven for 90 minutes, tenting it lightly with aluminum foil after 60 minutes, until a cake tester inserted into the center comes out clean. Remove the cake from the oven, and after 5 minutes turn it out of the pan to cool on a rack. Serve the cake warm or at room temperature; store it well-wrapped at room temperature.