Wikipedia
Mustamakkara (literally black sausage) is a type of Finnish blood sausage traditionally eaten with lingonberry jam. It is nowadays available in many stores across Finland, but is held in the position of local delicacy and speciality of Tampere. Mustamakkara is at its best when bought and eaten fresh at market stalls, to which it is delivered hot in styrofoam boxes from the factories directly after baking. A typical practice of reheating the sausage is to just fry it in a pan.
Mustamakkara is known to have been eaten as early as in the 16th century and was generally cooked over a small fire, in a hot cauldron or in an oven. Mustamakkara is made by mixing pork, pig blood, crushed rye and flour, after which it is stuffed into the intestines of an animal like most sausages. The major producer of this food is Tapola.
When buying mustamakkara in the Tampere region it is customary to specify the amount of money to spend instead of weight, length or number of pieces. Often people also choose by simply pointing at the preferred piece. The shape and moisture of mustamakkara varies and by this means the buyer can get the piece best suiting his or her taste. Also common is to indicate purchase of a complete sausage by requesting an "out-and-return" menopaluu which refers to its U-shape.