In a medium bowl, combine coffee and chocolate syrup. Add boiling water and mix well until chocolate and coffee are completely dissolved.

Add the cold water and mix well.

Pour mixture into a 9×13-inch pan and cover well. Place the pan into the freezer and freeze for about five hours. The mixture should not be frozen solid, only slushy.

Meanwhile whip the heavy cream in a bowl until stiff peaks form. Add the maple syrup and vanilla extract. Mix with a rubber spatula until syrup and extract are incorporated into the heavy cream.

Divide coffee-chocolate mixture into four tall mugs and top with maple-flavored heavy cream.