These crisp butter cookies incorporate blitzed toffee in place of some of the sugar and butter for a rich caramel flavor.

To really amplify that almond-toffee essence, the cookies are topped with sliced almonds, and a nutty brown-butter icing is sandwiched in between.

Be sure to roll the cookies very thin (about the thickness of two stacked pennies) so they stay crisp and light.

The sturdy sandwiches have a long shelf life, making them ideal for shipping.