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 to 30 minutes, stirring frequently. The rice should become tender and the mixture should thicken noticeably. Remove and discard the lemon peel and cinnamon stick.
03 - Stir in granulated sugar, butter, and vanilla extract. Continue cooking for 2 to 3 minutes, stirring until the sugar completely dissolves.
04 - Whisk egg yolks in a separate bowl. Gradually ladle small amounts of the hot rice mixture into the yolks while whisking continuously. This prevents the eggs from curdling.
05 - Return the tempered yolks to the saucepan. Cook over low heat, stirring constantly, for 2 to 3 minutes until the mixture slightly thickens. Do not allow it to boil.
06 - Pour the custard into individual ramekins or a single large serving dish.
07 - Mix 2 tablespoons granulated sugar with ground cinnamon. Sprinkle evenly over the surface of the custard.
08 - Allow the rice custard to cool to room temperature. Serve warm or refrigerate and serve chilled.