Preheat oven to 350 degrees F (175 degrees C). Grease and flour one 9x13 inch pan.
In a medium bowl, mix together the flour, baking powder, baking soda, and salt.
In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla. Beat in the flour mixture alternately with the yogurt.
Fold in the apples. Pour into the prepared pan.
Bake for 40 to 50 minutes in the preheated oven, or until a knife inserted into the center of the cake comes out clean.
Cool before serving.
Interesting Facts
Whole wheat flour is a healthier alternative to all-purpose flour as it contains higher levels of fibre, vitamins, and minerals.
This cake is best served warm with a scoop of vanilla ice cream.
This cake can be stored in an airtight container for up to three days.