Making the Caramel:

• In a medium saucepan, combine the granulated sugar, water, and lemon juice (if using). Stir gently until the sugar dissolves.

• Increase the heat and bring to a simmer. Allow the mixture to bubble and cook for 8-10 minutes, without stirring, until it turns golden brown.

• Once the caramel reaches a deep amber color, remove it from the heat. Quickly pour the caramel into the bottom of your flan dish or ramekins, swirling the dish to coat the bottom evenly. Allow it to cool and harden as you prepare the flan.

Making the Flan:

• Preheat your oven to 350°F (175°C). Prepare a large baking dish or roasting pan. Fill it with hot water for the water bath.

• In a large bowl, whisk together the sweetened condensed milk, evaporated milk, eggs, granulated sugar, vanilla extract, and a pinch of salt until smooth.

• Carefully pour the custard mixture over the cooled caramel in the flan dish, ensuring the caramel is undisturbed.

• Place the flan dish into the prepared roasting pan with hot water, ensuring the water comes halfway up the sides of the flan dish.

Baking the Flan:

• Bake for 50-60 minutes, or until the flan is set but still slightly jiggly in the center. To test, insert a toothpick—it should come out clean with just a few custard crumbs attached.

• Remove from the oven and allow it to cool in the water bath for 15 minutes. Then, remove the flan from the water and let it cool completely at room temperature. Refrigerate for at least 4 hours or overnight to fully set.

Serving:

• To serve, run a knife around the edges of the flan to loosen it. Invert it onto a plate with a lip to catch the caramel sauce. Slice and serve chilled.