Overheard an exchange at the supermarket today. An elderly (English) lady asked an (English) employee, "Where are the scones?" And he replied "There are scones just there." She laughed and said "You say scons, I say scoans. It's just one of those things." I recall debating with friends in Illinois nearly 20 years ago about what the "correct" pronunciation of scone was--that is, which was the more British. But, as our little supermarket drama points out, they're both English. John Wells at University College London has done a survey (NB: link is pdf file), finding that two-thirds of the 2000 Britons surveyed prefer the pronunciation that rhymes with con. He found no differences between the north and the south of England, but Scotland is solid 'scon' territory.
One of my favo(u)rite in-class activities is to have my students work in teams to create lexical field box diagrams (a way of representing the relations between word meanings) for terms for baked goods. This never fails to create vigorous debate, as one needs to decide things like "Is a scone a bread or a cake?" or "Is a bagel a type of roll?" Part of what makes the debates so complicated is the differing extents to which American English has infiltrated the class. (God help any American exchange students in this activity.) Not only is the range of baked goods in the two countries quite different (and taste preferences are quite different too), but even the words for the common items are often different.
Scones are sometimes likened to American biscuits, which is kind of true. But scones and biscuits are only as similar as British muffins are to what Americans call English muffins. Superficially, they look the same, but the tastes and textures are quite different. American muffins (e.g. blueberry muffins) have made their way here and become quite popular, though I have heard older people react to them with puzzlement--"that's not a muffin, that's a cake!"
The most recent Waitrose Food Illustrated magazine includes a letter to the editor that calls for a campaign to resist the word cupcake for what would traditionally be called a fairy cake (pictured) in BrE. To me, the two things are a bit different, with fairy cakes being smaller and typically a specific kind of sponge cake (traditionally with icing), whereas a cupcake is a cup-sized cake of any sort. You can get fairy cakes of other types, but the assumption upon hearing "fairy cake" is that it's a vanilla sponge.
British biscuits would be called crackers in AmE if they're savo(u)ry or cookies if they're sweet, but American cookies have made definite inroads here in the past few years, with cookie shops like Ben's Cookies (my favo(u)rite: peanut) and Millie's Cookies (my favo(u)rite: raspberry and white chocolate) serving American-style cookies. One wouldn't call those biscuits, as they're soft. My dad (what a guy!) sent me Christmas cookies the last time I was in England for the holidays. (One needs familiar baked goods at holidays, I think, and in the UK it's all about mince pies [AmE prefers mincemeat pies].) I showed Better Half how we put a slice of bread in the cookie tin in order to keep the cookies soft. He looked at me in horror and said, "Why would you want to do that?"
Digestive biscuits, or digestives for short, are somewhat like American graham crackers--though they differ in shape (round vs rectangular), and I often find digestives to be a bit greasier than graham crackers. My personal favo(u)rite UK biscuit is the malted milk biscuit (pictured), or if I'm feeling super-naughty the milk chocolate malted milk biscuit--with a layer of chocolate on the bottom.
One could go on and on about baked good differences. Ok, one will.
As an American, I can make a sandwich using sliced bread, a roll, a bagel, whatever. In the UK, sandwiches are made with sliced bread, and anything else is called by the name of the bread it's in--for example, a ham and cheese baguette. A bacon roll is bacon inside a roll that's been sliced in half (usually with ketchup or brown sauce), and is a popular hangover treatment. Just to confuse you, a sausage roll is not a sausage sandwich made with a roll, but a sausage baked in flaky pastry. The closest American equivalent is a pig-in-a-blanket, which, when and where I was a child, referred to a sausage (often a hot dog), wrapped in bread or (American) biscuit dough and cooked. Nowadays, I mostly see it referring to sausages wrapped in pancakes (about which more below).
Baps (BrE; pictured left) are soft rolls for making sandwiches with, and also a crude term for a woman's breasts. (Channel 4 recently ended an advertisement for the film [AmE prefers movie] The Gift with "...and Katie Holmes gets her baps out!" Apparently, the highlight of the film.) Baps (the baked kind, too) are softer than a Kaiser roll (AmE; pictured right), more like a hamburger bun, though American hamburger buns are typically rather brown on the outside, and baps aren't. Better Half tells me that barmy cake is a Northern term for a bap or a bap-like roll, but I've found little printed evidence of it, besides a number of sandwich shop names. [Postscript: see comments for a correction.]
Hamburger bun is odd to English ears because buns are usually thought of as being sweet, such as Chelsea bun (pictured), currant bun and hot cross bun (also found in the US).
The god of British baked goods is the crumpet (pictured), which is kind of cheating, as it isn't actually baked. Crumpets are made on a griddle, though I've never known anyone who makes their own. They are heavenly, and because of their relation to American pancakes (though crumpets have yeast), I like to eat them very un-Britishly with butter and maple syrup, but they're equally euphoria-inducing with raspberry jam. (American pancakes, by the way, are thicker than British pancakes, which are more like crèpes. We eat them with different things and at different times. Be cautious in ordering "American pancakes" in UK restaurants, as they're often not cooked all the way through. A lovely British tradition is treating Shrove Tuesday, i.e. the Tuesday before Ash Wednesday, as Pancake Day.) The last time I was in the US, the international section of our megasupermarket had something called crumpets, but they looked nothing like the kind you get here. They looked more like thick, misshapen pancakes. I didn't dare try them, as the disappointment of a bad (and overpriced!) crumpet would be very, very keen. Pikelet is another (regional) word for crumpet, sometimes specifically applied to a flatter type of crumpet. Crumpet, you probably know, is also dated (sometimes crude) slang for an attractive person (usually a woman) or sometimes a term of endearment.
Of course there are many many more cakes and breads and rolls and such that are different in the two countries, but my main aim here (as ever) was to point out differences in the language for them. I'm sure others will fill in some of the items I've missed here...