Preheat oven to 350 degrees and line an 8×8 pyrex pan with parchment paper.

In a bowl combine the cake ingredients and whisk to combine.

For the filling, in a medium saucepan combine apples and water and bring to a boil then reduce heat. Simmer, covered for about 5 minutes until apple are tender.

In a small bowl combine ¼ cup coconut sugar, 1 tsp. arrowroot, 1 tsp cinnamon and ½ tsp nutmeg. Pour that into the apple mixture and stir, cooking until thickened and bubbly.  

In a separate smaller bowl combine the topping ingredients into a crumble mixture.

Pour ½ of the cake batter into the prepared pan and spread out evenly.  Then take the apple filling and and sprinkle it evenly over the batter.

Scoop the rest of the batter on top of that and spread it out evenly and finish it by sprinkling the topping mixture  evenly on top. 

Bake the coffee cake for 40-45 minutes or until a toothpick inserted comes out clean (or with small crumbles).