Preheat the oven to 350°F (175°C). Line an 8"x8" pan with a sheet of parchment paper.
In a medium bowl, mix together the dry ingredients (almond flour through nutmeg). Set this aside.
1 3/4 cups + 2 tablespoons (188 grams) finely ground blanched almond flour, 3 tablespoons + 2 1/4 teaspoons (30 grams) coconut flour, 3/4 teaspoon baking soda, 3/8 teaspoon salt, 1 1/2 tablespoons ground cinnamon, 1/4 teaspoon ground nutmeg
In a large bowl, mix together the eggs, oil, maple syrup, coconut sugar, and vanilla.
3 large eggs, 7 1/2 tablespoons (105 grams) refined coconut oil, 1/2 cup (160 grams) maple syrup, 1 tablespoon vanilla extract, 3 tablespoons (36 grams) coconut sugar
Add the dry mix to the wet and mix just until combined.
Gently fold in the grated apples and then the chopped apples.
3/4 cup (120 grams) peeled and coarsely grated apples, 1 3/4 cups (220 grams) Granny Smith apple chunks
Pour the batter into the pan and bake for 20-24 minutes or until a toothpick inserted in the middle comes out clean. Let cool completely before frosting, about 1 hour.
In a small saucepan, mix together the maple syrup, cashew butter and coconut oil over medium heat. Add salt, if using (starting off with 1/8 teaspoon and adding more, if needed). At first it might not appear to come together well but be patient.
2/3 cup (160 ml) maple syrup, 7 tablespoons (112 grams) cashew butter, 1/3 cup (75 grams) refined coconut oil, 1/8 - 1/4 teaspoon salt
Stirring constantly, bring to a boil and while continuing to stir constantly, boil for about 2 minutes. It should have thickened a bit and become glossy. If it hasn't, boil for up to another minute. If you use a heavy bottom pan, you may need to boil it a little longer. Stir in the vanilla until well combined.
2 1/2 teaspoons vanilla extract
Let cool about 5-10 minutes and then pour over the cooled cake. Top with chopped nuts, if desired.
Store the frosted cake in the refrigerator for up to 3 days.