Preheat oven to 425 F. Line 6-8 muffin cups with paper liners and set on a baking sheet.
In a medium bowl, whisk together the flour, baking powder, baking soda, salt and cinnamon. Set aside.
In a large bowl with an electric mixer or the bowl of a stand mixer, add the butter and white sugar and beat well for about 2 minutes. Add eggs one at a time, beating well between additions. Add vanilla and beat to combine. Add flour mixture, a bit at a time until all added, then add sour cream. Fold in cranberries by hand.
Scoop batter in to muffin cups. Top with a slice of apple, then sprinkle generously with turbinado sugar.
Bake in pre-heated oven for 18-20 minutes, then check. If already golden enough, loosely lay a piece of aluminum foil over-top. Continue baking another 5 minutes, or until a tester inserted in the centre comes out clean.
Remove muffins from muffin tin on to a cooling rack to cool.