Beat together eggs, yolks, sweetened condensed milk, whole milk
and espresso in a large bowl with an electric mixer, or process
in a blender or food processor until smooth.
Cook the 1 cup sugar in a small heavy saucepan or copper caramelizing
pot over medium heat. Stir constantly until the sugar turns a honey
color. As the sugar begins to dissolve, stir only occasionally.
Once it dissolves, continue cooking without stirring until the caramelized
sugar is deep amber in color. The color will change rapidly, so
watch the saucepan carefully. Immediately after you remove the caramelized
sugar from the burner, pour it into an 8-inch soufflé dish. Quickly
tilt the dish in various directions so that the caramelized sugar
coats the bottom and sides.
Carefully pour the coffee mixture into the soufflé dish, and then
place them in a water bath, any shallow pan large enough to hold
the dish with room to spare and filled with 1 inch of hot water.
Bake the flan on the middle rack in a preheated 350 degrees F oven
for 1 hour, or until a knife inserted comes out clean.
Remove the flan from the oven and carefully lift the dish from the
water bath. Allow the flan to cool to room temperature, and then
chill it in the refrigerator for at least 3 hours. Unmold the flan
by first running a non-serrated knife along the inside edge of the
dish. Next invert the flan onto a serving platter. The caramelized
sugar syrup will cascade over the flan. Cut the flan into 6 wedges
to serve. Garnish each portion with some of the sugar syrup.