In your first bowl, sift together your flour, powder, spice and salt.
In your second bowl, cream together your sugar and egg.
Tip in your butter and yogurt/sour cream.
Fuse the two bowls together--add your first bowl into your second bowl in 3 separate additions. Don't worry too much about lumps, mix until just combined.
Pour into a greased tin and layer your apple slices on top. Sprinkle generously with cinnamon sugar and bake at 375 for about 17-19 minutes. Broil on high for a couple minutes just to begin caramelizing the sugar on top.
Recipe by The Squishy Monster at http://www.thesquishymonster.com/2012/11/adventures-in-singledom.html