Chill a mixing bowl and the ice cream maker bowl (if using an ice cream maker)
Prepare an ice cream base:
Combine 2 cups heavy cream
Combine 1 cup whole milk
Add 1/2 to 3/4 cup sugar (to taste)
Add 1/4 tsp salt
Add 1–2 tsp vanilla extract (or other flavoring)
Heat the mixture (optional for a thicker custard-style cream):
Warm cream/milk mixture over medium-low heat until steaming
In a bowl, whisk 4 egg yolks with 2–3 tbsp sugar until smooth
Slowly whisk hot mixture into yolks
Return to a saucepan and cook, stirring constantly, until thick enough to coat a spoon (about 170–175°F / 77–80°C)
Strain if desired and stir in vanilla
Cool the base:
Refrigerate at least 4 hours or overnight
Churn:
Pour into an ice cream maker and churn until soft-serve consistency (typically 20–30 minutes)
Freeze:
Transfer to a container
Freeze 2–4 hours (or until firm)
Serve:
Let sit 5–10 minutes at room temperature for easier scooping