1. Heat & Steep: Combine cream, milk, lemon zest (peel the lemon with a vegetable peeler (no pith) , half the sugar + dextrose, and salt. Heat gently to 175–180 °F for 10 minutes (steaming, not boiling). Remove from heat and steep another 10 minutes.
2. Prepare Yolks: Whisk egg yolks with remaining sugar + dextrose until slightly pale.
3. Temper: Slowly whisk about ½ cup hot dairy into yolks, then return mixture to saucepan. Note adding hot diary too quickly to the eggs may cook them.  Add slowly. 
4. Cook Custard: Cook on low, stirring constantly, until 180–183 °F. Do not exceed 185 °F. Custard should coat the back of a spoon.
5. Chill: Pour custard into a large measuring cup and cool that container quickly in an ice bath. 
6. Add Lemon Juice: When custard base has cooled to 50 F, add lemon juice.
7. Steep: Cover measuring cup and store in fridge for 6-12 hrs.
8. Freeze: Pour into a Ninja Creami container (max ~680 mL). Freeze flat 12–24 hours. 
9. Spin: Process on ICE CREAM. If crumbly, add 1 Tbsp milk (optional) and re-spin once. 

Technical Notes 

•Dextrose lowers the freezing point more effectively than sucrose, yielding a creamier texture.