For Cookies:
8 ounces all purpose flour
4 ounces rolled oats
1/2 ounce cocoa powder
2 ounces dried apple rings
3 ounces unsalted butter
2 1/4 ounces neutral flavored oil, like safflower
7 ounces sugar
1 1/2 ounce molasses
3 ounces corn syrup
1 1/2 teaspoon baking soda
1/2 teaspoon baking powder
1/2 teaspoon salt
1/4 teaspoon ginger
1/4 teaspoon cinnamon
1/4 teaspoon mace
1 egg
2 ounces milk

For Marshmallow Filling:
1 1/4 teaspoons gelatin powder
2 1/2 ounces water, divided
1 3/4 ounces corn syrup
4 1/2 ounces sugar
1/4 teaspoon salt
1 teaspoon vanilla extract
1 ounce unsalted butter