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 and dust 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.
To make fun shapes, prepare 2 8-by-8 inch pans and divide the marshmallow mixture among them. Let cool and set at room temperature, about 2 hours. Brush your favorite cookie cutters with oil and cut out. Overall yield will vary depending on the shape and size of the cookie cutters you use.