Maybe this recent thread will hold a clue. Or maybe there is a better recipe in here.

Here is a link that might be useful: Apple bread/cakes

Caliloo, I have a very similar recipe that is truly one of my favorites. It has been around for many years and I suspect that someone was updating the old recipe to make it healthier with whole wheat flour, egg whites and less oil. Ths biggest difference I see is that my recipe calls for 1 and 1/2 cups of oil.

Apple Cake

Mix and beat together:
3 cups AP flour
1 tsp soda
1 tsp salt
2 cups sugar
1 1/2 cups corn oil
3 large eggs
2 tsps vanilla ext.

Stir together and fold in:
3 cups chopped apple
2 Tbsp lemon juice
1 cup chopped nuts (I use pecans.)

Grease and flour a 9 x 13 pan. Bake at 350 for 1 hour.

Topping. Boil for 2 1/2 minutes. Pour over hot cake and leave in pan.
1 stick butter
1 cup light brown sugar
1/4 cup canned milk

There's a mistake in that recipe.......you have 3 cups of flour 2 cups of sugar and only about a cup of anything remotely liquid.
Lindac

Alexa, I think the problem is the leavening. Baking soda needs something acid to react with, and here that is only the apples. Apple cake recipes are sometimes like this, and I guess they may work if the apples are acidic enough and juicy enough and in small bits, LOL. But things will be more certain if you replace the soda with a tablespoon of baking powder.
I also think the baking time is possibly too long in a flat pan. That's how long you'd bake it in a tube pan.

I wonder if you could add applesauce instead of more oil (as called for in the recipe from adoptedbygreyhounds). I do that often in quick bread recipes when it seems there's just way too much oil in the batter. It does sound like you need some more liquid, and the baking powder would probably help too.

Call me crazy but I also think that maybe Splenda doesn't have quite the moisture qualities that sugar does. I don't know all the chemical ins and outs, but I do know that sugar makes fruit moist and juicy after a few minutes. If I want to healthy up a cake, I do sub egg whites (2) for whole eggs, and use more whole wheat flour, and I cut the sugar 1 cup down to 2/3 cup. These lower fat baked goods are somewhat less moist and do not keep as well as the full sugar recipe. But I've not noticed anything as bad as hockey puck situations. I have subbed Splenda for some of the sugar in a choc. chip cookie recipe and the cookie got pretty hard once it cooled, not chewy like the real thing.

While Splenda works quite well for sweetening drinks and making pudding and pie fillings, I have never liked it for baking. I have ruined more than one recipe trying to use it. I have a fried who uses twice as much Splenda as the amount of sugar called for and says it will work that way. I never bake with it at all.

Thanks for all the input!

ABG - that recipe does look very similar, I bet someone did take that one and try to "healthy it up". Also - interesting to know about the Splenda substitution not working as well..... I will try it again with real sugar in a lesser amount and maybe add some applesauce (or low fat sour cream) to add moisture.

You all are the best!

Alexa