Make the Cognac Caramel: In a small saucepan off heat, combine water, sugar, corn syrup, and salt. Place over low-medium heat and avoid stirring to prevent crystallization. Once the sugar dissolves, gently swirl the pan if it’s caramelizing unevenly. Remove from heat once caramel reaches an amber color (between 360-370°F). Pour in heavy cream slowly, whisking continuously. Stir in butter and Cognac and let cool.
Make the Gingerbread Crust: Process gingersnap cookies in a food processor until finely ground. Add remaining ingredients and pulse until the butter is evenly distributed. Line an 8x8 cake pan with parchment. Press half the crust mixture into the bottom of the pan and freeze for 20 minutes. Remove and cover, placing back in the freezer. Press the remaining crust into the pan and freeze.
Make the Ice Cream & Assemble: In a large bowl, whisk together sweetened condensed milk, vanilla, salt, and Cognac until smooth. Whip the heavy cream until stiff peaks form. Gently fold the whipped cream into the condensed milk mixture. Spread ⅓ of the ice cream mixture over the bottom crust, swirl in caramel, and repeat with two more layers. Cover with plastic wrap and freeze until firm, at least 8 hours or overnight. Place the frozen top crust on the ice cream and cut into bars or squares.
