In a small bowl, mix cinnamon and brown sugar together and set aside. In a mixing bowl, add butter and sugar, then combine until fluffy. In a separate bowl, whisk together flour, salt, and baking powder, then set aside. Sprinkle a couple of TBLS of the brown sugar and cinnamon mixture and 1 TBLS of the flour mixture over the chopped apple until coated; set aside. Once the butter and sugar are mixed well, add one egg at a time; mix until incorporated before adding the next. While the mixer is on low speed, add half the flour mixture, alternating with the cream, until all the flour and cream are combined. Fold in sour cream and vanilla by hand until no streaks remain. Pour half the mixture into a greased 9x5-inch bread pan, place half the cut apples, and sprinkle with half the cinnamon and brown sugar mixture; repeat with the remaining batter and apples, then top with the rest of the cinnamon sugar mixture. Bake at 350°F for 50 minutes, checking for doneness until a toothpick comes out clean. Let stand in the pan for 10 minutes and then remove, slice, and serve warm or at room temperature. Store covered at room temperature for up to a week.