Preheat the oven to 300 F / 150 C.
Peel and dice the apples.
In a pan, add the diced apples, brown sugar, cinnamon, and water. Cook on medium-high heat, stirring occasionally, until the apples are softened.
Add the dry ingredients to a bowl and mix until combined.
In a separate bowl, add the wet ingredients to a bowl and mix until combined.
Slowly add the wet ingredients to the dry ingredients, mixing to ensure there are no lumps.
In an 8x8 or circular springform pan, pour roughly 40% of the cake batter. Evenly spread the apples on top and then cover with the remaining cake batter.
Bake at 300 F / 150 C for 50-55 minutes.
Enjoy!