Brush the porcini mushrooms and remove tops from stems. Cut the stems into small cubes. Peel the shallots and dice finely. Heat 1 tablespoon of butter sauté 2 of the shallots and the diced porcini stems. Deglaze with red wine and simmer for about 10 minutes while stirring. Season with salt and pepper.
Heat 1 tablespoon of butter and sauté the remaining diced shallots. Add the vinegar, bring to a boil and reduce to by half. Add the chicken stock and boil down again by half.
Peel and rinse the potato and cut lengthwise into four thick slices. Heat 3 tablespoons of oil in a pan and fry the potato slices, turning to brown evenly. Rinse the calf's liver and pat dry. Cut into four portions. Heat 2 tablespoons of butter and saute the liver for 3-4 minutes. Place the porcini mushroom tops on the sides of the pan and braise briefly. Season with salt and pepper.
Cut the remaining chilled butter into small pieces and whisk into the sauce. Do not allow sauce to overcook. Season with salt and pepper.
Rinse the chives, shake dry and in small rings. Place the potato slices on plates and spoon some of the porcini pieces and sauce over top. Next, place a slice of the liver and porcini tops on top. Sprinkle with chives and garnish with fried garlic flowers, if desired.