Combine the water and sugar for the caramel in a small saucepan, bring to a light boil and cook -without stirring for 8-10 minutes – or until the mix starts to turn a rich amber color.
Carefully pour the hot caramel into a baking mold, you can use individual molds/ramekins or a 8-9 inch square or round baking mold.
Blend the eggs, eggnog, sugar, and vanilla.
Strain the mix and pour it into the baking mold or ramekins that already have the caramel in them.
To prepare the water bath, put the baking mold(s) into a deep larger baking pan, add water until it reaches about ½ the level of the baking mold(s) with the flan in them.
Bake at 350F / 175C for 30 minutes, then lower the heat to 325F/165C and bake for another 15-30 minutes. The exact time will vary on the size of molds, but it should be about 1 hour for the larger molds and about 45 minutes for the individual molds/small ramekins. The flan should slightly jiggly, but firm.
Remove the eggnog crème caramel flan(s) from the oven and let it cool down at room temperature for about 20-30 minutes. Then refrigerate for a few hours before serving.
To remove the flan from the mold, place the mold in a bowl with water for a few minutes. Then use a knife to gently oosen the edges.
Put the mold upside down on a plate and gently pat it until it releases. Let the caramel drizzle all over the flan. Serve inmediately.