Peanut Butter Swirl Ice Cream

Heat milk in a small saucepan over medium heat until just hot. Meanwhile, beat sugar and eggs together in a medium bowl until thick and pale yellow.

Gradually whisk hot milk into egg mixture in bowl, then pour milk–egg mixture into saucepan. Return saucepan to medium-low heat and cook custard, stirring constantly with a wooden spoon, until it is thick enough to coat the back of the spoon, about 5 minutes. Remove saucepan from heat and stir in 1⁄2 cup of the peanut butter. Strain custard into a large bowl, let cool briefly, stirring often, then stir in cream and vanilla. Cover and refrigerate until cold, 6–8 hours.

Process mixture in an ice cream maker according to manufacturer's directions, adding 1⁄2 cup of the chopped nuts to the ice cream 30 seconds before it has finished churning. Transfer to a bowl, quickly swirl in remaining 1⁄2 cup peanut butter, cover, and freeze until hard. Serve ice cream sprinkled with the remaining 1⁄2 cup nuts.