Whisk the sugar and lemon juice together in a bowl until the sugar has dissolved.
Add in the milk, heavy cream and zest and stir to combine.
Pour the mixture into a gallon sized bag and squeeze out as much air as possible when closing the bag.
Place the bag on a metal baking sheet and put it in the freezer for 4-6 hours or until frozen.
Take the sherbet out of the bag and break the slab up into pieces.
Put the pieces of frozen sherbet in a food processor and blend until smooth. Enjoy now if you prefer soft-serve! Otherwise, scoop sherbet into a metal bread pan, cover and freeze to solidify it more.
Notes
Recipe makes 3 small ½ cup servings. I would recommend doubling the recipe if you want bigger serving sizes.
The recipe is not overly sweet. You can taste the tangy lemon. If you prefer sweeter desserts, you may want to add more sugar.