01 - Combine the 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 to 30 minutes, stirring frequently, until rice is tender and mixture has thickened considerably. Remove and discard lemon peel and cinnamon stick.
03 - Stir in granulated sugar, butter, and vanilla extract. Continue cooking for 2 to 3 minutes, stirring until sugar has completely dissolved.
04 - Whisk egg yolks in a separate bowl. Gradually ladle small amounts of hot rice mixture into yolks while whisking continuously to temper and prevent curdling.
05 - Return tempered yolks to saucepan. Cook over low heat, stirring constantly, for 2 to 3 minutes until mixture coats the back of a spoon. Do not allow to boil.
06 - Pour custard into individual ramekins or a single large serving dish.
07 - Mix remaining 2 tablespoons sugar with ground cinnamon. Sprinkle evenly over surface of custard while still warm.
08 - Allow custard to cool to room temperature before serving. Can be served warm or refrigerated until chilled.