In a saucepan combine granulated sugar (½ cup) and milk(1 cup). Whisk in lightly beaten eggs(2 large) and place over medium heat until steaming (6-8 minutes), while stirring constantly.
Once steaming, remove from heat and stir in heavy whipping cream(1 ½ cups), peanut butter(½ cup), and vanilla extract (1 teaspoon).
Place mixture in glass bowl and cover with saran wrap. Place in refrigerator for 3-4 hours until thoroughly cooled.
Pour mixture in ice cream maker and churn until gelato becomes a soft-serve consistency. (Because gelato is egg-based, it will not crystallize or get as hard as much as normal ice cream.)
Notes
Although best served fresh, you may store gelato in airtight container placed a plastic ziplic bag.