Preheat your oven to 350 degrees. Spray a 9 inch bread pan with cooking spray
In a large bowl mix together the flour, salt, cinnamon, baking soda, and baking powder.
In another medium bowl mix together the eggs, butter, yogurt, sugar, and vanilla.
Mix the wet ingredients into the dry, being careful not to over-mix. Stir in the diced apples. Pour the batter into the prepared bread pan
Mix the ingredients for the bread topping, the butter, brown sugar, oats, and cinnamon together in a small bowl with a pastry cutter or fork and sprinkle over the unbaked bread.
Bake the bread for 60 minutes or until a a toothpick inserted into the middle of the bread comes out with just a few crumbs.
After 10 minutes, remove from the bread pan and set on a cooling rack. Allow to cool completely before wrapping tightly in plastic wrap.