Heat oven to 350. Grease a 9-inch springform pan and cut a parchment round for the bottom.
Toss the apples and cranberries with the cornstarch until the cornstarch is dissolved. Set aside.
In a food processor, grind the pecans until they are very finely chopped but not a paste, 20-30 seconds.
In a medium bowl, mix together the pecans with the flour, baking powder, cinnamon, and salt.
In another bowl, mix together the Greek yogurt, milk, vegetable oil, and vanilla.
Put the flat beater on your standing mixer. Add the eggs and the sugar to the bowl. Mix on medium high speed for 5 minutes. The batter will be very light colored and flow off the beater in a stream.
Turn the mixer to low. Begin adding the flour and yogurt mixtures in turn. Start with 1/3 of the flour, then 1/2 of the yogurt, and continue 1/3, 1/2, 1/3. Be careful not to overmix and only mix just enough to incorporate each addition.
Spread 1/3 of the batter onto the bottom of the prepared springform pan.
Mix half of the apples and cranberries with the rest of the batter and spread it in the pan. Then add the remaining fruit, pressing it in a bit so it is sitting in the batter.
Bake the cake for 50-55 minutes, or until a skewer comes out clean or until a thermometer reads between 205-210F.
Let it rest on a cooling rack for about 15 minutes. Then remove the ring of the springform pan and let the cake cool completely.
To serve move the cake onto a serving platter (removing the pan base), mix together the cinnamon sugar, and sprinkle it over the top.