01 - Combine the 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 to prevent sticking.
02 - Reduce heat to low and cook for 25 to 30 minutes, stirring often to ensure even cooking, until the rice is tender and the mixture has thickened noticeably. Remove and discard the lemon peel and cinnamon stick.
03 - Stir in the sugar, butter, and vanilla extract. Continue cooking for 2 to 3 minutes, stirring until the sugar has completely dissolved and the mixture is smooth.
04 - Whisk the egg yolks in a separate bowl until smooth. Gradually add a few spoonfuls of the hot rice mixture to the yolks while whisking continuously to temper them and prevent curdling.
05 - Return the tempered yolks to the saucepan. Cook gently over low heat, stirring constantly, for 2 to 3 minutes until the mixture thickens slightly. Do not allow to boil or the eggs may scramble.
06 - Pour the custard into individual ramekins or a large serving dish, ensuring even distribution.
07 - Mix the 2 tablespoons granulated sugar with the ground cinnamon. Sprinkle evenly over the surface of the custard.
08 - Allow the rice custard to cool to room temperature before serving. Serve warm for a comforting treat or chilled for a refreshing dessert.