Sandwich cookies are made by joining two cookies together with a sweet filling.
Just as a regular sandwich is created with two slices of bread similar in size, a cookie can be assembled with two identically-sized cookies, attached with a bit of tasty filling. Rolled cookies (cut with the same cookie cutter or even a drinking glass) or pressed cookies (formed with a cookie press or pastry bag) are most often used to make cookie sandwiches since they can be made uniform in size.
Cookie fillings have a stiff texture, or if thin when mixed thickens when set. Almost any icing, jam, spread, ganache – from marshmallow crème to peanut butter to prepared frosting – will do.
To assemble cookies, spread a small amount of the filling over the bottom half of a cookie. Place another cookie over the filling, bottom side down, and press gently.
Two classic sandwich cookies familiar to most of us are the Oreo cookie, made of two chocolate cookies with vanilla icing filling, and the whoopie pie, made of two soft cookies with vanilla crème filling.
Any favorite frosting or icing recipe can be modified to become a cookie filling. By adding an egg white or meringue powder, you ensure the filling thickens and stiffens as it sets.
Combine ½ cup butter (room temperature) at low speed with 2 cups powdered sugar and 2 teaspoons vanilla until blended. Turn the mixer up to high and beat for 2 or 3 minutes more until fluffy. This combination makes enough filling for about 3 dozen 1-inch cookies.
Cream cheese is spreadable, yet has a thick consistency suitable as a cookie filling. Beat 4 ounces of cream cheese until it is light. Mix in 1 teaspoon vanilla and 2 cups of powdered sugar, a bit at a time, until smooth. Spread on cookies. This combination makes enough filling for about 3 dozen 1-inch cookies.
Chocolate cream cheese filling: add 3 tablespoons cocoa powder along with powdered sugar.
Jam and cream cheese filling: add ¼ cup seedless jam or jelly to the cream cheese mixture, beating until smooth.
Ganache, a mixture of chocolate and cream, is a classic cookie filling. To make ganache, simmer 6 tablespoons chocolate chips and ¼ cup half-and-half in a small saucepan over low heat for 1-2 minutes, stirring several times until chocolate melts and is smooth. Remove from heat. Allow ganache to cool. Spread on cookies. This combination makes enough filling for about 3 dozen 1-inch cookies.
Replace dark chocolate with white chocolate chips, mint chocolate chips, peanut butter chips, or butterscotch chips.