Pre-heat oven to 325 degrees, and use cooking spray to coat a 9 x 13 pan.
In a mixing bowl, combine eggs, milk, sugar, and vanilla. Beat with electric mixer until combined but not foamy.
Stir in the cooked rice with a wooden spoon. Pour mixture into a 9 x 13 baking dish. Sprinkle with cinnamon.
Place dish inside a rimmed cookie sheet and place on the top rack of the oven. Use a pitcher to pour water into the cookie sheet to a depth of 1 inch. This allows the egg custard to bake evenly.
Bake for 30 minutes and stir the custard, scraping the bottom of the pan. At this point, you may also stir in the raisins (optional). Bake for another 15 to 20 minutes or until a knife inserted near the center comes out clean.
Serve warm or cold. Top with chopped pecans (optional). To store, cover and chill.