Shred or grate 4 apples into a large bowl. Add the remaining ingredients and stir to combine. Thinly slice the last apple and lay in a single layer across the bottom of an oiled 9x13 pan.
Meanwhile, whisk the coconut cream/coconut milk and coconut sugar together and heat in a small saucepan over medium heat. Bring to a soft bowl and then lower to a simmer for 15 minutes, until it thickens and reduces a bit, whisking occasionally to prevent burning. While it reduces, whisk together tapioca starch and water in a separate bowl. After 15 minutes is up, remove saucepan from the burner and whisk in vanilla extract, tapioca mixture and salt. It should thicken quickly so continue to whisk until it has the consistency of caramel. It should taste like salted caramel, so adjust sweetness and salt level to your preference.
Once the caramel cools slightly, slowly pour 1/4 of the caramel into the oat mixture while stirring to temper the egg. Pour the remaining caramel over the apple layer at the bottom and then spread the oat mixture over. Bake at 375 for about 35 minutes until firm and slightly crisp on the top.
Top with walnuts or dairy-free vanilla yogurt. Store in the refrigerator. It’s even better cold!