Preheat oven to 300º F. Cream butter/margarine and the sugar, then add the flour and eggs in alternating additions, mixing after each. Beat the batter well before adding the extracts. After those are mixed in thoroughly, add the finishing cup of 7UP. It will fizz and look strange, but rest assured this is supposed to happen. Mix it in until the batter looks uniform, then pour into a 9 x 13 greased and floured pan. Bake for about an hour and fifteen minutes.
NOTE: Contrary to what you might think, you DON'T need baking powder or baking soda for this recipe, it WILL rise and it rises beautifully. It is dense like a pound cake. Some recipes have a suggested glaze, usually prepared from lemon juice, confectioners' sugar, and sometimes coconut, but I think this cake tastes better pure and plain, and believe me it is plenty sweet enough to NOT need icing.