In a small bowl, stir together the oats, brown sugar, cranberries, cinnamon, and salt.
With a paring knife or melon baller, remove the core of each apple, creating a deep, wide well. Make sure not to cut to the bottom of the fruit! Using a vegetable peeler, peel away an inch-wide layer of skin from the top of each apple.
Pour 1/2 teaspoon of maple syrup into each apple. Divide the oats mixture evenly between the apples, filling the wells. Drizzle the top of each apple with 1/8 teaspoon of olive oil.
Place the apples in a 13-x-9-inch baking pan. Fill the pan with 1/2-inch water. Cover with aluminum foil and bake for 1 hour to until the apples are tender when pierced with a knife.
Serve warm or at room temperature. May be stored in an airtight container in the refrigerator for one day. Oatmeal mixture may be made up to two days before.