-
1
Preheat oven to 350u00b0 and line two baking sheets with parchment paper.
-
2
In a bowl, whisk together flour, baking powder, salt, baking soda, and cinnamon.
-
3
In bowl of a mixer fitted with the paddle attachment, beat butter and sugars on high speed until light and fluffy, about 3 minutes. Scrape down sides of bowl and beater. On low speed, mix in egg and vanilla. Add flour mixture and mix until just combined, then stir in oats by hand.
-
4
Roll dough into 23 or 24 balls (2 level tbsp. each). Arrange 6 balls on each baking sheet, 2 in. apart (remaining cookie dough balls can be frozen). Bake cookies, rotating pans halfway through, until golden brown and crisp, about 14 minutes. Let cool on pans.
-
5
Line a small baking sheet with parchment paper. Set 6 cookies on sheet, bottom sides up, and center 1 scoop ice cream (about 1/3 cup) on top of each. Press down on ice cream with back of a spoon to flatten it slightly, then top with a second cookie. Freeze until hard, at least 2 hours.
-
6
Pour room-temperature Chocolate Shell into a bowl. Working with 1 ice cream sandwich at a time, use a slotted spoon to lower it into Chocolate Shell, flipping to enrobe sandwich in chocolate. Lift out sandwich, letting excess chocolate drip off, and return to parchment-lined baking sheet. Repeat with remaining sandwiches and chocolate.
-
7
Freeze sandwiches until hard, at least 1 hour or up to overnight. (If storing longer, wrap each in waxed paper and put in an airtight container.)
-
8
*If ice cream is airy, you may need as much as 4 cups, because it will collapse when measured.
-
9
Make ahead: Up to 2 months, wrapped in waxed paper and frozen airtight.
