In a large bowl, combine the eggs, sugar and oil. Combine the flour, cinnamon, baking soda, baking powder, salt and nutmeg; beat into egg mixture. Stir in carrots., Pour into two greased and floured 9-in. round baking pans. Bake at 350° for 35-40 minutes or until a toothpick inserted in center comes out clean. Cool for 10 minutes before removing from pans to wire racks to cool completely., For frosting, in another large bowl, cream butter and cream cheese until light and fluffy. Beat in vanilla. Gradually beat in confectioners' sugar. Add enough milk to achieve desired spreading consistency. Reserve 1/2 cup frosting for decorating if desired. If desired, stir walnuts into remaining frosting. , Spread frosting between layers and over top and sides of cake. If decorating the cake, tint 1/4 cup reserved frosting orange and 1/4 cup green. Cut a small hole in the corner of pastry or plastic bag; insert #7 round pastry tip. Fill the bag with orange frosting. Pipe twelve carrots on top of cake, so each slice will have a carrot. Using #67 leaf pastry tip and the green frosting, pipe a leaf at the top of each carrot. , Store cake in the refrigerator.