Combine 1/2 gallon milk, sugar, and rice in a large saucepan over medium-low heat. Simmer, covered, for 1 hour, stirring frequently. Remove the pan from heat and let sit for 10 minutes.
Whisk together eggs, 1/4 cup milk, vanilla, and salt in a large bowl until well combined.
Stir into rice mixture and return the pan to low heat, stirring constantly, for 2 minutes.
Pour pudding into a 9x13-inch dish and cover with plastic wrap, folding back the corners to allow steam to escape. Allow pudding to cool to room temperature.
Remove plastic wrap and sprinkle the surface of pudding with cinnamon. Cover tightly with fresh plastic wrap and refrigerate for 8 hours to overnight before serving.
Enjoy!
