Nice to have a full exposure of what is a biscuit for English native people.
For cultural difference in France a biscuit is restricted to sweet backed products, mostly of sponge with (biscuit irlandais) or with less (biscuit genoise) or without butter (biscuit Savoie) . Still the meaning is extended to some more dry and less sponge small cakes usually with no or few garniture. Not used for bars (Twix, mars…)
Mars isn’t a biscuit in England either, it’s a chocolate bar.
A biscuit needs to actually contain the “biscuit”, the, uh, crumbly dough stuff.
Then again, I consider pink wafers a biscuit, and they don’t seem to have any dough… I actually have no idea what they’re made of.
On the topic of sponge, my feeling is that sponge is contrary to the idea of a biscuit in English. This is one reason why a classification of a jaffa cake as a biscuit is controversial.
Going back to cookies, I see there as being two types of cookie: the soft full-sized cookie and the hard mini cookie, and I only consider the latter as biscuits.
for a DIY of wafers, the “biscuit” part is accessible, but the “garniture” a bit complex (sugar cooking, white of eggs is my guess+aroma (strawberry?). Maybe you can use premade stuff for covering cakes you buy in a shop for backeries
not… quite… American biscuits are significantly less sweet than scones, and have a bit more in common with bread rolls. You wouldn’t put gravy on a scone, and I’d imagine an american wouldn’t typically think of such either, but you would on an american biscuit.
I just learnt ffrom this video that what I said about jaffa cakes was wrong: VAT (currently 20%) is levied, in the UK, on chocolate-covered biscuits but not cakes, rather than the other way around (which would seem more intuitive.)
So the classification of jaffa cakes as cakes was, in fact, a legal victory for the corporation.
I recommend watching it, it gives a pretty nice overview of the history of this area of mathematics, does one of the best explanations of the first incompleteness theorem (I think I may steal this if I ever have to teach it) and additionally treats Turing’s halting problem.