Preheat oven to 350 degrees F.
Grease and flour a 12 inch bundt pan.
Beat together the butter and sugar until light and fluffy, and then add eggs and and vanilla and mix until smooth.
In a separate bowl, mix together the flour, baking powder, baking soda, and cinnamon.
Add this dry mixture 1/3 at a time, alternating with yogurt.
Mix after each addition just until combined.
Fold in the apples and pour into the prepared pan.
Bake for about 35 to 40 minutes or until a skewer comes out clean.
Cool, and if desired, sift a little powdered sugar on top before serving.