Gingerbread Apple Upside-down Cake

I am woefully behind on posting new recipes because we've been cooking too much lately and I've had a bit of a difficult week. This cake, though, was the perfect way to use up some of the apple-picking overabundance. It also keeps extremely well in the fridge.

Gingerbread Apple Upside-down Cake (from Smitten Kitchen, originally Karen Bates via NYTimes)

Ingredients
Topping
4 tablespoons butter, plus extra for greasing pan
1/2 cup dark brown sugar
Pinch of salt
4 apples (about 1 3/4 pounds - I did it based on weight and used 6), peeled, cored and cut into 1/4-inch wedges
Batter
1/2 cup (1 stick or 4 ounces) butter, at room temperature
1/2 cup sugar
1 large egg
1/3 cup dark molasses
1/3 cup honey
1 cup buttermilk
2 1/4 cups flour
1 teaspoon baking soda
1/2 teaspoon salt
1 teaspoon ground ginger
1 teaspoon cinnamon

1. Preheat the oven to 325°F. Grease a 10-inch cake pan.
2. Make the topping: Melt butter in a small saucepan. Add brown sugar and simmer over moderate heat, stirring, four minutes, then swirl in salt.
3. Remove from heat and pour into the bottom of your cake pan. Make circles of overlapping apple slices on top of the caramel. Chop any remaining slices and place them in the gaps.
4. Make the batter: Using a mixer, blend 1/2 cup butter and the sugar on medium-low speed. Increase the speed to high and cream until light and fluffy.
5. In a medium bowl, whisk together the egg, molasses, honey and buttermilk.
6. In a separate bowl, sift together the flour, baking soda, salt, ginger and cinnamon.
7. Alternate mixing the flour and molasses mixtures into the butter mixture, adding the next once the last has been incorporated.
8. Pour the batter into the pan. Bake at least 45 to 50 minutes or until a wooden tester inserted into the center of the cake comes out clean.
9. Let cool on a rack for 10 to 15 minutes, then turn out onto a platter (one that will catch spills).