If you have an immersion blender: Zest the lemon over the sugar (avoid the white pith) into a heavy bottomed, non-reactive pot. Rub the zest into the sugar to release the oils. Add the eggs and salt then use the immersion blender to blend until there’s no egg white that’s unmixed.

If you don’t have an immersion blender and are using a regular blender or food processor: start by adding the sugar to a bowl and zest the lemons into it (avoid the white pith) and rub the zest into the sugar until it’s like wet sand. Set the sugar in the blender/food processor and add the eggs, then blend until smooth and there’s no unmixed egg bits. Transfer to a non-reactive pot (stainless steel or enamel coated cast iron).

Add the heavy cream and lemon juice to the pot and quickly whisk to combine. Set the pot over medium heat. Whisk as it heats, it will turn into a smooth liquid. Stir frequently as it thickens - it will thicken first on the bottom, whisk/stir to ensure it cooks evenly. When the temperature reaches 175 F remove from heat. Pour though a fine mesh sieve into a bowl.

If serving individual desserts, divide the pudding into the bowls and once they are at room temperature cover with plastic wrap and set in the fridge to chill for at least four hours, until cool and thick.

If using as a filling later, set the pudding in a container that has a lid - once it’s at room temperature, cover and chill for 6-8 hours before using. The pudding will keep in the fridge for about 5 days, if you need it to keep longer freeze it.