01 - Combine rice, whole milk, heavy cream, lemon peel, cinnamon stick, and salt in a medium saucepan. Bring to a gentle simmer over medium heat, stirring occasionally.
02 - Reduce heat to low and cook for 25–30 minutes, stirring frequently, until rice is tender and mixture has thickened. Remove lemon peel and cinnamon stick.
03 - Stir in sugar, butter, and vanilla extract. Continue cooking for 2–3 minutes until sugar dissolves completely.
04 - Whisk egg yolks in a separate bowl. Gradually add spoonfuls of hot rice mixture to yolks while whisking continuously to prevent curdling.
05 - Return tempered yolks to saucepan and cook over low heat, stirring constantly, for 2–3 minutes until slightly thickened. Do not allow to boil.
06 - Pour custard into individual ramekins or a large serving dish.
07 - Mix 2 tablespoons granulated sugar with ground cinnamon. Sprinkle evenly over custard surface.
08 - Allow rice custard to cool to room temperature. Serve warm or refrigerate until chilled.