Step 1
Preheat oven to 375 degrees F (190 degrees C). Line 2 baking sheets with parchment paper.
Step 2
Stir cake mix eggs oil and vanilla extract together in a bowl. Shape dough into 1-inch balls. Arrange 2 inches apart on the prepared baking sheets. Coat a glass lightly with flour; flatten each dough ball into a cookie.
Step 3
Bake in the preheated oven until cookies are slightly golden at the edges 6 to 8 minutes. Transfer to wire racks to cool completely.
Step 4
Place ice cream in the bowl of a stand mixer fitted with the paddle attachment. Blend on low speed until uniformly softened 10 to 15 seconds. Add marshmallows; blend until incorporated.
Step 5
Line a rimmed 9x13-inch baking sheet with aluminum foil. Spread ice cream on top. Freeze until firm 5 hours to overnight.
Step 6
Line a baking sheet with parchment paper. Spread 1 to 2 teaspoons frosting on the bottom of each cookie. Place 12 cookies frosting side-up on the baking sheet.
Step 7
Remove ice cream from the freezer. Cut ice cream into rounds using a 2-inch cookie cutter. Place ice cream rounds onto the cookies using a spatula or by pressing them out of the cookie cutter with a spoon. Press another cookie on top frosting-side down.
Step 8
Place baking sheet in the freezer until ice cream cookie sandwiches are firm 8 hours to overnight.
Step 9
Pour sprinkles into a bowl. Roll each ice cream sandwich in sprinkles. Place 1 sandwich into each sandwich bag; fold the edge and crease to seal. Freeze for 1 to 2 hours.
Step 9
Peel down bag as you eat keeping the bag underneath to catch drips.