Butter 6 8-inch ramekins.
Place all ingredients in a heavy saucepan and cook over high heat, stirring constantly until caramel turns golden brown and runs clear (without traces of granulated sugar).
Pour the caramel into prepared ramekins and set aside to cool.
Heat both types of milk and the coffee extract in a heavy saucepan over medium heat until just before boiling.
When bubbles begin to form around the edges of the pan, remove from heat.
Whisk the eggs and egg yolks into the milk mixture.
Pour the mixture into the prepared ramekins.
Place ramekins in a casserole pan and fill pan with hot water to reach 1/2 to 2/3 of the way up the sides of the ramekins.
Bake at 325 degrees for 30 to 45 minutes or until the skin on the top of the custard is set (no longer sticky).
Remove from oven and let cool.
Heat sugar and water in a heavy saucepan over medium heat until the mixture turns a golden color (to about 270 degrees; when mixture forms brittle threads when dropped into ice water, it is ready).
Drizzle onto greased aluminum foil or greased parchment paper in swirls and other desired designs.
Allow to cool (this takes only a few minutes).
Remove swirls with a spatula and use to garnish cooled flan, as liberally as desired.