Preparation: Preheat your oven to 180°C (350°F). Grease six 3/4-cup ramekins and set aside for later use.

Caramel Layer: In a small saucepan, mix 1/2 cup of Allulose with water. Heat it over low heat until it begins to simmer, then increase to medium heat. Stir regularly until the mixture thickens and achieves an amber-brown color. Evenly distribute the caramel among the prepared ramekins, ensuring the sides are well-coated.

Custard Mixture: In another saucepan, combine your chosen milk and the remaining Allulose. Bring to a gentle simmer on low heat, then remove from heat. Whisk in eggs, vanilla extract, and salt until the mixture is smooth. Strain this mixture evenly into each ramekin.

Baking: Place the filled ramekins in a large baking dish. Pour boiling water into the dish until it reaches halfway up the sides of the ramekins. Bake for 45-50 minutes, or until the custard sets in the middle. Remove from the oven and allow to cool completely at room temperature. Refrigerate for at least 6 hours, or overnight, until set.

Serving: To serve, run a moist knife around the edges of each ramekin, then invert onto a plate to release the flan.