Liver with Vinegar

• 1 pound calfs or lambs liver, cut in thin slices
• 2 tablespoons butter
• 1 tablespoon extra-virgin olive oil
• Salt and pepper
• 2 cloves garlic, crushed
• 1 1/2 teaspoons crushed dried mint (optional)
• 1/4 cup wine vinegar

1. If serving as an appetizer, cut the liver slices into 1 1/2-inch pieces, but leave the slices whole if serving as a main dish.
2. Saute the liver in a mixture of butter and oil over medium heat very briefly, for a minute or so, adding salt and pepper and turning the pieces over, until lightly colored but pink inside.
3. Remove from the pan and put aside.
4. Add crushed garlic and mint, if you like, and when the aroma rises, stir in the vinegar.
5. Return the liver to the pan and cook 1/2 minute more, turning the pieces over.
6. The liver should still be a little pink inside.
7. A different sort of tartness can be obtained by sprinkling with 1 tablespoon ground sumac instead of adding vinegar.
8. Fry 1 sliced onion in the butter and oil until soft, before adding the liver.

calfs, butter, extravirgin olive oil, salt, garlic, mint, wine vinegar

Taken from www.epicurious.com/recipes/food/views/liver-with-vinegar-373435 (may not work)