01 - Combine rice, whole milk, heavy cream, lemon peel strips, cinnamon stick, and salt in a medium saucepan. Bring to a gentle simmer over medium heat, stirring occasionally to prevent sticking.
02 - Reduce heat to low and cook for 25–30 minutes, stirring frequently, until rice is tender and mixture has thickened into a creamy consistency. Remove and discard lemon peel and cinnamon stick.
03 - Stir in granulated sugar, butter, and vanilla extract. Continue cooking for 2–3 minutes, stirring until sugar completely dissolves.
04 - Whisk egg yolks in a separate bowl. Gradually add 2–3 spoonfuls of hot rice mixture to yolks while whisking continuously to gently warm them without curdling.
05 - Return tempered yolks to saucepan. Cook over low heat, stirring constantly for 2–3 minutes until mixture thickens slightly. 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 surface of custard.
08 - Let custard cool to room temperature. Serve warm or refrigerate until thoroughly chilled.