Preheat oven to 350. Grease an 8x8 square pan.

In a mixing bowl, stir together the melted butter and the brown sugar. Add the egg and vanilla and mix until smooth. Stir in the flour, salt, oats, apples, and butterscotch chips. Spread the batter into the prepared pan and bake in the preheated oven about 20-25 minutes or until set on top and golden on the edges, but still somewhat gooey in the center. Allow them to cool at least 15 minutes before cutting into bars. Great served warm or room temperature. Best enjoyed the same day.