Grain-free, lower-sugar version of my Grandma's Apple Cake

My Grandma's Apple Cake recipe is one that we make every year in my family. It heralds the fall, it's simple, it can be made so easily with pantry ingredients, and it requires no frostings or glazes or anything more than itself. But it also has a lot of sugar! This year I decided to see if I could make a grain-free, lower-sugar version of the cake, and that recipe is below. The picture is not super glamorous, and I think I should have baked it longer, but overall it was a successful experiment. (Next time I might add 1/4 cup more almond flour, or maybe try adding a bit of coconut flour in there to absorb more of the liquid.)

Frances's Apple Cake, modified to be grain-free and lower-sugar

1/2 cup oil
1 3/4 cup coconut sugar
2 eggs
5 cups apples, diced (I used Mutsu, my favorite baking apple, but you can try any combination)
2 cups almond flour
3/4 cup tapioca flour/starch
2 tsp baking powder
1 tsp baking soda
1 tsp salt
1 tsp vanilla
1 tsp apple pie spice (optional)
1/2 cup walnuts

This recipe came to me with just ingredients, but in general I mix the diced apples with sugar, then the beaten eggs and vanilla, then mix in the dry ingredients, nuts last. I often leave out the nuts or use hazelnuts instead.

Bake at 350 F for 45 minutes to 1 hour in a 9x13 pan.