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 25–30 minutes, stirring frequently, until the rice is tender and the mixture has thickened noticeably. Remove and discard the lemon peel and cinnamon stick.
03 - Stir in the granulated sugar, unsalted butter, and vanilla extract. Continue cooking for 2–3 minutes, stirring until the sugar has completely dissolved and the mixture is smooth.
04 - Whisk the egg yolks in a separate mixing bowl until smooth. Gradually ladle small amounts of the hot rice mixture into the yolks, whisking continuously to temper and prevent curdling.
05 - Return the tempered yolks to the saucepan. Cook over low heat, stirring constantly, for 2–3 minutes until the custard thickens slightly. Do not allow the mixture to boil.
06 - Pour the custard evenly into individual ramekins or a large serving dish, depending on your presentation preference.
07 - Mix the remaining 2 tablespoons granulated sugar with the ground cinnamon. Sprinkle evenly over the surface of the custard while still warm.
08 - Allow the rice custard to cool completely to room temperature. Serve warm or chilled according to preference.