In a medium non-reactive saucepan, combine zest and sugar. Use your fingers to massage the together until fragrant and moist.,

Add remaining ingredients and use a silicone whisk to combine. Let the lemon mixture rest about 5 minutes to infuse the liquid with the lemon.,

Heat the pudding mixture over medium heat, whisking constantly. Bring to a simmer and cook until it begins to thicken, about 10 minutes. Remove from heat.,

Place a fine mesh sieve over a heatproof bowl and pour the pudding to strain any solids.,

Press a piece of plastic wrap directly touching the surface of the pudding to prevent a skin from forming on top. Chill completely before serving, about 2-3 hours.