Set oven to 180ºC . Three buttered 8or 23 cm round cake pans. To make the cake, sift together the flour, baking soda, and salt. Beat the shortening with the butter until well combined. Cream in the sugar and beat until fluffy and light. Beat in the egg yolks one at a time until well combined. Add the flour mixture alternately with the buttermilk, beginnng and ending with the flour mixture. Stir in the orange zest, cereal (broken into shreds), cranberries, and pecans. Beat the cream of tartar into the egg whites and continue beating until stiff. Gently fold the whites into the cake batter. Pour into the 3 prepared pans. Bake in pre-heated oven 25 to 35 minutes, until a toothpick inserted in the center comes out clean. Cool on racks. To make the frosting, beat the cream cheese with the butter until well combined. Gradually add the sugar and orange juice; beat until creamy and smooth. Stir in the orange zest. Frost the tops and sides of the cake.