if you think onion dip comes from a packet of onion soup, my friend, you are missing out. I know you know how to make caramelized onions, so I refer you to the superior California Dip: https://altonbrown.com/recipes/onion-dip-from-scratch/
Oh yes! That’s actually why I learned to caramelize onions, to make that dip, although the technique is not the one he mentions there (I think that recipe has had some refinement). I’ll be interested to try that version of caramelized onions, which I do cook regularly because they freeze so well.
The problem for me was that a) I don’t like mayo or big chunks of onion in my dip and b) it’s so much work for something I felt wasn’t enough of a marked improvement over the original powder-and-sour-cream version. Like it’s good, but not THAT much better, at least to me.
I was more talking about -- yes there are from-scratch onion dips, but the vast majority of Americans just dump and stir, you know? It’s sort of the traditional method, as silly as that seems to say.
There's a thing called creme fraiche that I find in with the sour cream and other dairy at the poncy grocery I love for its deli. Seems like it's exactly what you're looking for, for this dip.
I’ve always thought it was just a substitute for sour cream, but admittedly I don’t think I’ve ever had it, I’ll have to check it out.
Now that you've had reduced cream, try canned Latin American "Crema", another condensed dairy product, available in the US in Latin markets and online. The way you described reduced cream made me think of Crema. I can't guarantee they'll taste sufficiently similar, but now you have the baseline to find out, and if they do you have an American source!
It’s true, part of why I really wanted to try the authentic stuff was so that I could flavor-match it to various dairy products in the US and see how they compared. I also think proooobably I could make my own by just...heating cream and continually remixing it rather than skimming the top off the way you would for clotted cream.
UNRELATEDLY, as regards the “buttermilk” discussion on the tea towel post -- I know in theory you can go with some milk swished up with a bit of vinegar, but I’ve always found that clots the milk and/or doesn’t give the wanted effect. Really the only thing I regularly use buttermilk for is buttermilk biscuits and you do need the real thing, there, to get the proper flavor. On the other hand buttermilk biscuits are such a pain in the ass that I don’t even make those anymore, so. :D Might give powdered buttermilk a try tho....
