Temper the egg yolks slowly to avoid scrambling. Don't skip the ice bath — it stops the cooking instantly and preserves the silky texture. Freeze your ice cream maker's bowl for a full 24 hours. Press plastic wrap directly onto the surface of the ice cream to prevent ice crystals. The custard base can be refrigerated for 3-4 days before churning. Churned ice cream keeps for 2-3 weeks. If too hard, let sit at room temperature for 10-15 minutes before scooping.