Wash the meat, dab dry and cut into 8 thick slices. Cut a pocket into each medallion. Roughly chop the walnuts. Mix the gorgonzola and nuts and put a heaped teaspoon in each pocket. Wrap filled medallions with bacon and stick them together with small wooden skewers. Heat oil in a frying pan and fry the medallions all around for 12-15 minutes.
Season with salt and pepper. In the meantime, put the beans in 1/4 litre of boiling salted water and cook for 4-5 minutes. Drain. Peel and finely chop the onion. Clean, wash, quarter, seed and cut the tomato into small cubes. Heat butter in a pot and fry the onion in it. Add the diced tomatoes and steam briefly. Add the beans and toss in. Remove medallions from the pan and keep warm. Deglaze frying fat with cream and let it boil down a little bit at medium heat while stirring occasionally. Season to taste with salt and pepper.
Heat butter in a pot and fry the onion in it. Add the diced tomatoes and steam briefly. Add the beans and toss in. Remove medallions from the pan and keep warm. Deglaze frying fat with cream and let it boil down a little bit at medium heat while stirring occasionally. Season to taste with salt and pepper. Arrange the medallions on plates together with the beans and sauce and serve garnished with parsley and walnuts as desired. Served with potato gratin