Line an 8-by-8-inch square baking dish
with overlapping sheets of parchment paper and a 2-inch overhang on at least two sides, brush the bottom and sides with vegetable oil
generously with confectioner's sugar, tapping out any excess.
Bring the apple cider to a simmer
in a small sauce pan over medium heat and reduce to 1/2 cup, about 6 minutes. Transfer it to a bowl. Sprinkle gelatin over cider and stir until dissolved. Set aside.
Add the granulated sugar
to a medium-large saucepan
with 2 cups water. Set over low heat and stir until all of the sugar dissolves, then turn the heat to high and cook at a rolling boil
until sugar reaches 250 degrees F, about 20 minutes. Turn off heat, stir in gelatin mixture (sugar will bubble up) and set aside. (If the gelatin mixture is too set, then microwave for a few seconds to loosen).
Add the egg whites to the bowl of stand mixer
fitted with the whisk
attachment and beat on high until stiff, turn the mixer to low and add the sugar-cider mixture in a slow and steady stream. Turn the mixer up to high and beat until the mixture is thick, doubled in volume and the whisk leaves thick ribbons when raised from the bowl, about 5 minutes. Add spices
and stir to combine.
Oil a rubber spatula
and scrape the mixture into the prepared pan and let cool and set at room temperature, about 2 hours.
Dust a baking sheet with more confectioners' sugar. Lift the marshmallows out of pan with the parchment handles, and dust the top surface with confectioner's sugar. Oil a knife or a pizza
cutter and cut the marshmallows as desired, re-oiling knife as necessary.
Transfer the cut marshmallows to the baking sheet and toss each until no longer tacky. Store in an airtight container for up to 2 weeks.