Cream butter and sugar until fluffy, add in eggs, mix well.
Add in milk and yogurt, mix well. Sift in flour, baking powder and baking soda. Mix until well-combined.
In another bowl, dice the apples into small cubes, mix with sugar and cinnamon.
Pour 2/3 batter into a lined baking tin, then add in apples. Top with remaining batter, sprinkle with cinnamon + sugar.
Pop in preheated oven at 180C, bake for 26 to 28 minutes or until fully cooked. Let it cool completely and enjoy!