1. Preheat oven to 325°F Place four 3/4-cup custard cups in 13x9x2-inch baking pan. Stir sugar and 1 tablespoon water in heavy small skillet over medium-low heat until sugar dissolves.
2. Boil without stirring until syrup is deep amber color, occasionally brushing down sides of skillet with pastry brush dipped into water and swirling skillet, about 8 minutes. Immediately pour syrup into custard cups, dividing equally.
3. Whisk milk and cinnamon in small saucepan to blend; bring to simmer. Cover and let cool 15 minutes.
4. Whisk eggs to blend in medium bowl. Gradually whisk in cinnamon milk, then sweetened condensed milk and vanilla. Divide among caramel-lined custard cups.
5. Pour enough hot water into baking pan to come halfway up sides of cups. Bake custards until set in center, about 55 minutes. Cool in water in pan. Remove custard cups from water; cover and refrigerate overnight.
6. Run small knife around custards to loosen. To unmold each, place small plate atop custard; firmly holding plate and custard cup together, invert and shake gently, allowing custard and caramel to settle onto plate.