FOR THE APPLES:
Wash and dry the apples, and core them. Scoop about a 1/2 inch of the apple out with a spoon to make room for the topping.
Rub the apple with the cut side of a fresh lemon where you scooped to prevent browning.
FOR THE CRUMB TOPPING:
In a food processor fitted with a blade or medium size bowl using a pastry cutter, add the cold butter, brown sugar, flour, oatmeal, sea salt and cinnamon.
Pulse all ingredients until crumbly. You should have about 2 1/2 cups, and any un-used crumb topping can be frozen for another use.
TO FINISH AND BAKE:
Scoop a heaping tablespoon into each apple - which is easier to do with the apple in your hand and the spoon of topping in the other. I fit about 1/4 cup into each apple.
Place the stuffed apples in an oven proof dish, and add the apple cider to the bottom, with or without the brandy.
Bake at 350 for about 40 minutes until you can easily poke the end of sharp knife in the side the apple to test for softness.
Serve warm with a spoonful of the cider sauce on top, and whipped cream or ice cream if you'd like.