This is the OP (original poster). Thanks all for the comments and suggestions.

Thanks to all your input, I have gotten closer to the "light" part of the flan I am questing after, with a mix of just eggs, sugar and milk/cream. Forget the evaporated milk, the sweetened condensed milk, etc.

However, I still cannot seem to get the "airy" part of this flan we had in Cuba.
and I HAVE been cooking all the ones I've tried in the oven in a water bath.

I do understand now from all your feedback that what I thought made it "airy" (the little bubbles we saw all through it) was due to overbaking, so not the "clue" as to what made the texture so great. However, it was definitely "airy". As opposed to smooth. "Smooth" is how I would describe the way it was with the eggs, sugar and milk/cream recipe I tried. How to describe "airy" -- like the texture of a poached cheesecake is one way to describe it. Or maybe a very light chocolate mouse. Or even a souffle would be "airy".

any other thoughts on how to pull off this light and airy flan? I was thinking maybe adding in beaten egg whites?

This is the OP again. Having gotten discouraged and taken a break from my "quest for the best flan we had in Cuba." I read all your suggestions, and have now tried 4 recipes and all of them are "too dense." I am trying again for a party next Friday night, and will try Blue Room's recipe, unless others of you can help.
To clarify, the texture I am seeking is NOT like a souffle. It was definitely a flan but "light and airy" as opposed to how all the flans I have tried so far have come out, which I would call "dense", to one degree or another.
Wondering if this sheds any light on things -- a couple of months ago, I had a poached cheesecake, which had the same texture I am looking for in this flan.....but I already surrounded the ramekins with water...... is there something else about the recipe for a poached cheesecake that would help with my quest?!

This is the OP. Thanks lemons and all for trying to help. I think I may have figured it out ....... if you google "Cuban flan" you can see many pictures and recipes. I looked specifically at the single serving sized flans, as that is what we had. You will see -- Some images and recipes show a flan where the texture is all solid/dense; others show the edges of the flan filled with little air bubbles on the sides. The latter is what we had in this flan that tasted so great, and what I was trying to describe. I am going to compare the recipes for the ones with the air bubbles to those without, and see if I can figure this out. Of course your thoughts and suggestions most welcome.

Im the Original Poster. sorry for lack of clarity.
The one that I really liked was "airy", and yes it did have bubbles. As opposed to all the others we had, which I would describe as "denser".
It was also more tender and softer in the mouth than the other ones. Not that the other ones weren't also soft (how could a flan NOT be soft?!) but this one was more tender, and softer. As you said, more the texture of a light mousse or the meringue on a pie rather than the texture of something like cheesecake. Not OTOH, not as light and airy as the texture of a meringue. More like the texture of a whipped mousse, I'd say. and visually, it did have these air bubbles throughout.
The "light" and "airy" one was definitely NOT overbaked.

hope this clarification helps.

THANK YOU ALL so very much
we will have so much fun considering your suggestions and winnowing them down. The recent poster who suggested the 'compare and contrast taco adventure' and all the walking routes will be especially helpful but again, we will pour over all your suggestions. We have a gigantic used+new bookstore here in Portland whose T-shirts say, 'so many books, so little time.' Of your suggestions, we would say, 'so many restaurants to try, so little time'!! again thanks and if more suggestions, please continue!
susan

so here's what I think it's all about: even with the VitaMix, the peels take the longest to pulverize. And there were a few little bits that were just resistant to that final transformation. I didn't especially care that the soup was 100% liquid with no bits at all. The little bits that remained were really so few, and the pieces so tiny. But If I cared, I could have strained it. Or done it in smaller batches in the VitaMix. Or maybe just a longer time in the VitaMix. Or peeled the tomatoes.

thanks for all your input and the gazpacho clarification..............I got the recipe, though, from a local restaurant, and THEY called it gazpacho. So there you go.

this is Susan, the original poster. I think the VitaMix can be trusted to blend everything up, seeds, even cores (though I do cut those out). I think what I was really asking was whether you thought the recipe telling you/me to peel the tomatoes was about the peels being hard to get as finely ground as the rest of the tomato, or whether it might be a taste issue (like why you might peel a pineapple or something else where the skin as a different/more bitter taste than the rest of the fruit/vegetable)

So, one of our Passover traditions is seeing how STRONG our ground horseradish can end up. If you open the little container it's been stored in, and you swoon from the fumes, we consider it a good year. We always thought that the difference had to do with whatever root was purchased each year.

But from this thread, I can see perhaps it has more to do with how you make it. One hint is to WAIT to add the vinegar to let it get stronger/hotter. Like how long do you wait? 10 minutes? An hour?

Another hint seems to be to cover the bowl with a plastic bag, but I couldn't tell if that was to keep the fumes in the horseradish and not have them dissipate out, or it was to protect the cook?!

A couple of sites have suggested that the longer you store it, the stronger it gets -- but our experience is quite the opposite: by the next day, it is pretty wimpy. Maybe the trick is only to add the vinegar right before you want to serve it, I am wondering??

I think that last year sometime, I read an article (NY Times?) or heard on the radio (Lynne Rosette Kaspar??) about hints for making/keeping horseradish strong. Does anyone remember that source?

thanks in advance from the Potent Passover Horseradish Fanatics here in Portland Oregon!!