01 - Combine rice, whole milk, heavy cream, lemon peel strips, cinnamon stick, and salt in a medium saucepan. Bring to gentle simmer over medium heat, stirring occasionally to prevent sticking.
02 - Reduce heat to low and cook for 25 to 30 minutes, stirring frequently. The rice should become tender and the mixture will thicken considerably. Remove and discard lemon peel and cinnamon stick.
03 - Stir in granulated sugar, unsalted butter, and vanilla extract. Continue cooking for 2 to 3 minutes, stirring until sugar completely dissolves and butter melts into the custard.
04 - Whisk egg yolks in a separate mixing bowl until smooth. Gradually add 2 to 3 spoonfuls of hot rice mixture to yolks while whisking continuously to prevent curdling.
05 - Pour tempered yolks back into saucepan. Cook gently over low heat, stirring constantly, for 2 to 3 minutes until custard slightly thickens. Do not allow mixture to boil.
06 - Pour custard evenly into individual ramekins or a single large serving dish. Smooth tops with back of spoon for even presentation.
07 - Mix remaining 2 tablespoons sugar with ground cinnamon. Sprinkle mixture evenly over surface of custard while still warm.
08 - Allow rice custard to cool completely at room temperature. Refrigerate if serving chilled, or serve warm after cooling for 30 minutes.