Place the white chocolate in a heat-safe glass or metal bowl that fits snugly over a saucepan. Bring about one inch of water to a gentle simmer in the saucepan. Pour the heavy cream over the white chocolate and place the bowl on top of the saucepan to create a double boiler. Heat gently, stirring occasionally, until about half of the chocolate is melted. Remove from heat and continue stirring until fully melted and smooth. If needed, return briefly to the heat, being careful not to overheat. Stir in the lemon zest until evenly combined. Cover the surface of the ganache directly with plastic wrap and refrigerate for 1 to 2 hours until firm. Scoop portions using a tablespoon, roll into smooth balls, then roll in confectioners’ sugar or leave plain. Lemon Truffles should be served at room temperature for the best texture.