In a nonstick skillet, add 1 cup of sugar and spread out evenly. Turn heat to medium. DO NOT stir the sugar. Let it cook, without stirring until the sugar begins to melt. When it begins to melt, shake the skillet, do not stir with a spoon. Continue this until the sugar turns to a caramel color. Immediately have your pan ready and pour in the caramel. Swirl to coat the bottom evenly. Set aside.
Preheat oven to 350 degrees F. In a pot or tea kettle heat 6 cups of water to medium heat.
In a large bowl, whisk the eggs until well incorporated.
Gradually whisk in the milk products, vanilla, cinnamon and salt. Pour mix into pan with prepared caramel. Transfer to deep baking dish.
Transfer cornstarch to a small bowl. Whisk in 1 tablespoon of cold water until smooth. Whisk this slurry into the flan mix.
Pour mix into pan with prepared caramel. Transfer to deep baking dish.
Carefully pour the hot water into larger pan, making sure you do not get any water in the flan mix. The water may prevent it from setting up correctly. Carefully transfer to preheated oven.
The flan will bake in the water bath for 50 minutes to 1 hour and 5 minutes. When the flan just has a slight jiggle and a cake tester comes out clean, then it's ready. Remove from oven and let it sit for 10 minutes before you remove it from the water bath onto a cooling rack.
Let the flan cool for an hour before transferring it to the refrigerator. Let it chill for at least 6 hours. Before unmolding, loosen the edges with a small sharp knife. Place a larger platter or flat plate over flan. Hold tight with both hands and quickly flip it over. Let it sit for a few minutes. When you see the caramel running down, then carefully remove the pan to expose flan. Serve with fresh fruit or fresh whipped cream!