Combine 1/4 cup water and 3/4 cup sugar in heavy saucepan and place over medium-high heat without stirring. Let come to a boil and watch carefully for the color to change, swirling gently as needed if the sugar isn’t cooking evenly. When medium golden brown in color, off the heat and very slowly and carefully pour in the mezcal [seriously, only add just a few drips at a time while whisking, as it will will bubble intensely and create a very hot steam], whisking until the bubbling stops. Immediately pour caramel into ramekins, distributing evenly. Set aside.