What is Spotted ?

I live in Virginia, and there are a lot of Brits living here. I don't know how it works in the UK, but in the US if the grocery store doesn't have what you want, they can order it; so now we have an "international aisle" with many foreign foods. The Brits have ordered marmite, clotted cream, colman's mustard, boddington's pub ale, Heinz baked beans, and something that comes in a can called "spotted " What is it?