Combine the ginger, water and ¼ cup of sugar in a large, heavy-bottomed saucepan and bring to a gentle boil. Cook for about 5 minutes. While the ginger cooks, gently whisk the eggs with the remaining sugar and set aside. Add the heavy whipping cream and whole milk to the saucepan with the ginger, reduce the heat to medium and scald (bring it nearly to a boil, until the milk is steaming and bubbles are starting to form). Remove it from the heat and temper the eggs by pouring about a cup of the cream into the egg and sugar mixture, whisking constantly. Add the egg mixture to the saucepan, and set over medium heat. Cook, stirring constantly, until the mixture coats the back of a spoon. Stir in the salt, ground ginger and vanilla extract.
Pour through a strainer into a heat-proof container and chill. When you’re ready to churn, add the ginger liqueur (if using), stir, and process according to your manufacturer's instructions. Freeze until solid.
To assemble ice cream sandwiches- once your ice cream is frozen and your cookies are chilled, place a scoop of ice cream on one cookie and sandwich with the second cookie, pressing down gently. Smooth the edges with your finger if desired, wrap in plastic wrap, and freeze until ready to serve.
Recipe by oh honey bakes at https://ohhoneybakes.com/pumpkin-butterscotch-cake-molasses-cookies/