Preparation

Make the topping batter

• Position a rack in the center of the oven, and heat the oven to 350ºF.
• In a medium bowl, whisk together the cornmeal, flour, sugar, baking soda, and salt.
• Fold in the egg and sour cream with a silicone spatula until just combined.
• Fold in the butter a little bit at a time until just combined.

Prepare the cobbler

• In a large bowl, whisk the flour, brown sugar, crystallized ginger, ground ginger, 1 tsp. of the cinnamon, and the nutmeg. Toss the apples in the mixture to coat. Add the rum, and toss again.
• Grease a 10-inch cast-iron or other heavy-duty oven-safe skillet with the butter. Add the apple mixture, including any unabsorbed flour mixture.
• Dollop the batter in scant 1/4-cup mounds over the apples. Sprinkle the batter with the sanding sugar.
• Bake until the top is golden brown and the apples are tender, 55 to 65 minutes, rotating the skillet halfway through. If the top becomes golden brown before the apples are tender, loosely cover with foil to prevent overbrowning.
• Whisk the honey with the remaining 1/4 tsp. cinnamon. Drizzle on top of the hot cobbler. Serve warm with whipped cream or ice cream.