• Preheat the oven to 300°F (150°C). Mist an 8-inch (20 cm) round cake pan with cooking spray.

Make The Caramel

• In a medium saucepan, combine the sugar and ¼ cup (59 g) water and set over low heat. Increase the heat to medium and cook, occasionally swirling the pan to distribute the caramelized sugar—do not stir or the sugar will seize and crystalize—until the mixture is amber in color, 8 to 12 minutes. As soon as all the sugar has turned an amber color, quickly and carefully pour the caramel into the prepared cake pan. Let this cool for 5 minutes.

Make The Flan

• In a blender, combine the half-and-half, eggs, condensed milk, vanilla, and salt and blend until smooth, 20 to 30 seconds.
• Place the cake pan in a larger shallow metal baking dish like a roasting pan. Pour the flan into the cake pan and cover the cake pan tightly with foil. Fill the larger baking dish with warm or hot water to come halfway up the side of the cake pan.
• Bake until the outer rim of the custard is firm but the center still has some jiggle to it, 1 hour 15 minutes to 1 hour 30 minutes. Remove the cake pan from the water bath, then remove the foil completely and let cool at room temperature for about 1 hour. Place the foil back onto the cake pan and refrigerate until completely cool and set, at least 4 hours.