Combine coffee, water & Tia Maria, set aside until cool. Combine Nestle Sweetened Condensed Milk and cream in a large bowl and beat with an electric mixer until thick. Beat in half of the coffee mixture. Combine remaining coffee mixture with milk and brush well over both sides of sponge biscuits. Line a 20 cm square cake pan with aluminum foil. Spoon half of the cream mixture into the pan and top with biscuits. Top with remaining cream mixture and freeze until set.