In a medium saucepan, combine the rolled oats, milk, sugar, salt, vanilla extract, and cinnamon. Bring the mixture to a gentle boil over medium heat, stirring occasionally.
Once boiling, reduce the heat to low and let it simmer for about 5 minutes, stirring frequently until the oats are soft and the mixture thickens.
In a separate bowl, whisk the eggs until well beaten. Gradually add a small amount of the hot oatmeal mixture to the eggs, whisking constantly to temper them. This prevents the eggs from scrambling.
Slowly pour the tempered egg mixture back into the saucepan with the oatmeal, stirring continuously. Cook for an additional 2-3 minutes until the oatmeal is creamy and slightly thickened.
If using raisins, stir them in now. Remove from heat and let it cool for a few minutes before serving.
Serve warm, topped with fresh fruit if desired.