Caramel Sauce:
1 cup sugar
1 teaspoon vanilla
Flan:
1 cup milk
1 can evaporated milk
1 can sweetened condensed milk
5 eggs
1 egg yolk
1 teaspoon vanilla
1 teaspoon instant coffee dissolved in 1 tablespoon boiling water
1 tablespoon brandy
Place a round 9x2 inch cake pan in an oven on the lowest setting, about 200°. My oven only goes down to 250, so I usually leave it at 250° with the door cracked open.
Caramel sauce: Caramelize the sugar in a small, heavy saucepan. The right kind of pan is important: Using a skillet will not caramelize the sugar well. To caramelize the sugar, cook it over medium-low heat 5-8 minutes until it is golden brown and syrupy. Very quickly stir in one teaspoon of the vanilla; then pour the syrup into the warmed cake pan. Tilt the pan a little to ensure that the syrup evenly coats the bottom and sides. Set the pan aside to cool for a few minutes while you mix together the other ingredients. Raise the oven temperature to 325°.
Flan: Stir together the three milks. Add the eggs and egg yolks, mixing thoroughly. Stir in the vanilla, coffee, and brandy. Pour the mixture into the cake pan over the caramel syrup. Place the cake pan in a baking pan on the center rack in the oven. Pour two cups boiling water into the baking pan so that the cake pan is sitting in a bath. Bake for 1 hour or till knife inserted in center comes out clean.
Let flan cool completely on counter. Then cover in plastic wrap and chill in refrigerator 8 hours or overnight. To serve, run a small rubber spatula or knife around the edge of the cake pan (keeping the knife edge to the pan, not the flan), and just under the edges of the flan if necessary. Place a serving platter upside down on top of the cake pan. Quickly but carefully, invert the cake pan so the flan is upside down on the platter with the caramel sauce on top. Use a spoon if necessary to drizzle extra caramel sauce from the pan over the flan.
Tip: For easy clean up, soaking the cake pan in very hot water; it will dissolve the hardened caramel sauce.