2 cups whole milk
Pared or grated zest of just under 1/2 lemon
5 large egg yolks
1/2 cup sugar
In a small saucepan combine milk and lemon zest. Place over medium-low heat just until steaming; do not boil. Remove from heat, cover, and allow mixture to infuse for about 20 minutes.
In a medium bowl, whisk together egg yolks and sugar. Strain infused milk into a pitcher, then whisk it into yolk mixture.
Pour mixture into a clean saucepan, and place over medium-low heat. Stir constantly with a wooden spoon until it forms a custard thick enough to coat back of spoon, about 10 minutes. (Do not overheat or it will curdle.)
Cool mixture by placing bottom of pan in several inches of cold water; give it a stir. Transfer to a bowl and refrigerate until well chilled, about 1 hour.
Freeze in an ice cream maker according to manufacturer’s instructions.