It’s a frozen, round thing. The bombes of yesteryear were all made of layers of ice cream, basically a big half ball on a plate. Some people say they’re called bombes because they look like the type of bomb that Boris Badinov would throw on the Rocky and Bullwinkle show. Whether that’s true or not I have no idea. Others claim it’s because of the “surprise” middle that most bombes contain.
Whatever the case, it’s safe to say that the bombe has diversified considerably over the years. There are still lots of ice cream bombes, but more and more you find filled with mousse, creams, or semi-liquid sabayons. Some split the difference by using frozen mousse, which is what I think I’ll do.
Sure I could make my own ice cream and prepare the bombe the traditional way, but even my way-cool ice cream maker will still produce a slightly grainy product. A home-made mousse takes about the same amount of time to prepare, but of course that it doesn’t require a machine and will create a silkier end product.