Preheat the oven to 350°F. Next, cut the prunes into small pieces and place them in a small bowl. Pour hot, boiling water on top of the prunes, add in the baking soda, and allow them to soak for at least 10 minutes.
In a separate bowl, combine the flour and baking powder. Set aside.
In a large bowl, beat the honey, egg, vanilla extract, and coconut oil together.
Slowly, beat the prune mixture into the egg mixture.
Working in small portions and using a spatula, add the flour mixture into the wet mixture until well-combined.
Fold the peeled and chopped apples into the mixture.
Grease a 7-inch round baking dish and pour the batter into it. Bake for 45-50 minutes. Allow the cake to cool at room temperature. Slice and enjoy!