To prepare the caramel, add two cups of sugar and one cup of water to a saucepan. Bring to a boil over medium heat until the mixture turns a dark amber color, about 10 to 12 minutes.
Fill the greased flan molds with the prepared caramel, coating the bottom and filling just under the rim.
Preheat the oven to 340°F (170°C).
In a pot, add the pineapple juice, remaining 1 cup of sugar, and cornstarch. Cook on low heat, stirring occasionally, until the mixture comes to a boil and thickens. Set aside to cool.
In a bowl, add the eggs and beat on low speed until liquid.
Add the cooked pineapple mixture, brandy, milk, and vanilla extract, and mix until well combined.
Pour the flan mixture through a strainer into another bowl.
Fill the flan molds just under the rim.
Place the filled flan molds onto the water-filled baking tray. The water should reach halfway up the sides of the molds.
Bake for 40 to 50 minutes, or until the flan has set.
Let the flans cool completely, then refrigerate for a couple of hours.
Once cooled, gently invert onto a plate and refrigerate for at least 2 hours before serving.