• In a medium sized bowl add flour, baking powder, and salt. Mix together really well so the baking powder is distributed throughout.  Set aside.
• Peel and core the apples.  Cut the apples into small bits.  Place the apple bits, cinnamon and sugar in a small boat.  Stir to coat the apples and set aside.
• Grease a large bowl and set aside.
• Using your mixer with the paddle attachment  add the butter and egg yolks. Beat together about 3 minutes until it is fluffy and a light yellow colour.  
• Then add the sour cream.  Mix until blended.

Combining

• Add the apples to the dry ingredients, stir.
• With the mixer on low, slowly add the dry ingredients to the butter/sour cream mixture a little bit at a time.  Make sure the flour is incorporated before adding the next spoonful.
• Once done place the mixture in the buttered bowl.  Cover with plastic wrap and place in the fridge for at least an hour.

Cut and Roll Donuts

• Preheat oven to 350 F. On a floured counter roll out your dough until it's about an inch thick.
• Cut the dough with a donut cutter and place the cut dough into the baking donut pan. Bake at 350 for between 20-30 minutes.  Until the donuts are golden.

Glaze

• Place the icing sugar and the vanilla in a bowl.  Stir in the milk until it's a consistency you like.  The thinner the glaze the less sweet the donuts will be.
• As soon as the donuts are baked place the warm donut into the glaze. Flip over to do the other side and place on a rack to cool.