Method

Line heavy large baking sheets with parchment paper and set aside. Preheat the oven to 160 degrees C.

Finely chop the oats in a food processor. Mix in the flour, baking powder, bicarbonate of soda, and salt. Set aside.

Using an electric mixer, beat the butter and sugars in a large bowl until fluffy. Scrape down sides of mixing bowl. Beat in the eggs and almond extract. Add the flour mixture in 3 parts and stir just until blended. Stir in the chocolate chips and chopped almonds.

For each cookie, drop 1 rounded tablespoonful of dough onto the prepared baking sheets, spacing 2.5cm apart (do not flatten dough). Bake until the cookies are golden (cookies will flatten slightly), about 13 minutes. Cool the cookies on the baking sheets for 5 minutes. Transfer to a cooling rack and cool completely. The cookies can be prepared 1 day ahead. Store airtight at room temperature.

To make the ice cream sandwiches: Place the ice cream in a large bowl. Mix in the amaretto. Cover the ice cream mixture and freeze until firm, at least 3 hours.

Arrange 12 cookies, flat side up, on a baking sheet. Top each with a scoop of ice cream, then another cookie, flat side down, pressing slightly to adhere. Cover and freeze the sandwiches until they are firm, at least 3 hours. Sandwiches can be made up to 4 days ahead. Wrap each sandwich with plastic wrap and keep frozen.