Christmas food must be traditional; it must be the best we can provide; but above all it must be colourful! Here are kitchen-tested recipes which take care of all three "musts". CHRISTMAS CAKE Ingredients: (All spoons level)—3 oz. sugar, 4 oz. margarine, 1 tablespoon syrup, 8 oz. plain flour, 2 teaspoons baking powder, pinch of salt, 1 teaspoon cinnamon, 1 teaspoon mixed spice, 2-4 eggs, fresh or dried, 1 lb. mixed fruit, 1/2 teaspoon lemon substitute, milk to mix, fresh or Household. Method: Cream the sugar and margarine, add the syrup.