Soften the ice cream: Set the ice cream on the counter for 10–15 minutes to soften slightly. You want it scoopable, not melted.
Cream the butter and sugars: In a large bowl, beat butter, brown sugar, and granulated sugar until light and fluffy, about 2–3 minutes.
Add eggs and vanilla: Beat in the eggs one at a time, then mix in vanilla until smooth.
Combine dry ingredients: In a separate bowl, whisk flour, baking soda, baking powder, and salt.
Add to the wet mixture and mix just until combined. Fold in chocolate chips if using. Do not overmix.
Chill the dough: Cover and refrigerate for at least 30 minutes (up to 24 hours). Chilled dough bakes into thicker, softer cookies that are easier to sandwich.
Preheat and prep: Preheat oven to 350°F (175°C).
Line 2 baking sheets with parchment paper.
Portion and shape: Scoop heaping tablespoon-sized balls (about 1 1/2 tablespoons each) and roll into smooth rounds. Place 2 inches apart on the prepared sheets.
Bake: Bake 9–11 minutes, until edges are set and centers look slightly underdone. Soft centers are key for a good ice cream sandwich.
Cool completely: Let cookies cool on the sheet for 5 minutes, then transfer to a rack to cool fully. Warm cookies will melt your filling.
Prep the filling: If you want neat, uniform layers, spread softened ice cream about 3/4 inch thick in a parchment-lined 9x13-inch pan.
Freeze 30–45 minutes until firm enough to cut out rounds with a cookie cutter that matches your cookie size. Or simply scoop directly.
Assemble: Flip half the cookies upside down. Add a generous scoop of ice cream (or a cut-out round) to the center.
Top with another cookie and press gently until the ice cream reaches the edges.
Add coatings (optional): Roll the sides in mini chips, sprinkles, crushed nuts, or cookies. Press gently so they stick.
Freeze to set: Place sandwiches on a parchment-lined tray and freeze for 1–2 hours until firm.
Wrap and store: Wrap each sandwich tightly in plastic wrap or parchment, then place in a freezer bag or airtight container.
