Calves liver is soft and subtle and perfect for this dish. Although pork liver and even beef liver are sometimes used as well. For today I'm using calves liver and it's being served with sauteed onions and potato. I'm out of bacon (gasp!) or I would be having lovely crisp bacon as well.
Some people soak their liver in milk, I don't. If you've got nice liver it's a waste of milk. I do however give it a rinse and a nice pat dry.
My Omi always told me to never salt liver before you cook it. So a simple dredge in flour and my liver is ready for the pan.
I used a combination of butter and olive oil, and heated my pan up fairly high. My advice is to have everything else you're serving done. The liver wont take long to cook at all, maybe a minute and a half or two on either side.

Side one.
Some blood may leech out of the liver, that's not a problem.

Side two.
That's it. Plate the liver with your sweet sauteed onions and some nice salty potatoes and you've got a awesome dinner. Mum serves her liver and onions with a drizzle of aged balsamic, cracked black pepper and sea salt. I'm doing the same.
Make sure to not overcook the liver, or it will be dry and unpleasant. The center should still have a little ooze to it. My perfect bite is a bit of potato, a nice chunk of liver and some onions on top.
Calves liver is soft, but it has a more pronounced flavour than chicken liver. I'd say this is just above an entry level offal. If you are comfortable with chicken liver give this a try. The sweet and salty tips from the other elements of this dish make it very well balanced. The liver alone may be a tad strong for those a little wary of offal.

A treat for those who like liver.