I think I can help you with the recipe, but not the icing as I have never put icing on mine. Mine is called "German Raw Apple Cake" and was given to me by my husband's grandmother, so I have had it for over 40 years. I do believe she put some type of icing on it years ago, but I never thought it needed it as it was so good without it. Hope this helps.
German Raw Apple Cake
4 c. chopped raw apples
1 c. chopped nuts
Place apples and nuts in a large bowl and sift over the top:
2 c. flour
2 c. sugar
2 tsp baking soda
2 tsp. cinnamon
1 tsp. salt
Mix well until apples and nuts are coated.
Add a beaten mixture of 2 eggs, ½ c. oil and 2 tsp. vanilla
Mix well until all ingredients are blended.
Bake in oblong pan, greased and floured, for 45 min at 350-375 degrees.
As an interesting sidenote, my husband submitted this recipe for a fire department cookbook many years ago, but when they printed it, they left out the sugar. Made for a lot of phone calls after the cookbook was published with my DH's name as contributor.