- With the rack in the middle position, preheat the oven to 375°F (190°C). Generously butter the cavities of two silicone cookie pans.
- In a bowl, combine the flour, baking soda and salt.
- In another bowl, using a wooden spoon, combine the butter with the brown sugar and corn syrup. Add the egg yolk and stir until smooth. Add the dry ingredients and your chosen garnishes.
- Divide the dough into 8 equal parts. Using the spatula or your fingers, press a piece of dough evenly into each cavity of the cookie pans. Place the pans on a baking sheet.
- Bake for 8 minutes or until the cookies are lightly golden. Let cool completely on a wire rack, about 30 minutes.
- Place the ice cream insert (white piece) over one of the cookie pans. Place in the freezer for 15 minutes. Meanwhile, let the ice cream sit out at room temperature.
- Divide the softened ice cream between the cavities of the ice cream mould, pressing down firmly with the spatula. Place the cookie pan ice cream side down over the second cookie pan to form the sandwiches.
- Freeze for at least 1 hour before unmoulding, following the instructions on the ice cream mould. For more tender sandwiches, individually wrap each one in plastic wrap and freeze for 48 hours to let the cookies soften. In this case, let the sandwiches sit out at room temperature for 5 minutes before eating.