Place all sauce ingredients into a sauce pan. Bring to a boil. Reduce heat and simmer while preparing the other ingredients.
Heat a medium sauce pan on medium heat. When hot, add a small amount of olive oil. When oil is shimmering. add leeks. Cook until soft, about 4 minutes.
Add walnuts to pan with leeks. Cook until the walnuts are browned and fragrant, about 5 minutes.
Add beans to pan with leeks and walnuts. Mix well, turn heat to medium low. After the beans are hot, about 3 minutes, set the heat to low until the mushrooms are ready.
While the beans are heating, remove the stem and degill the mushrooms with a spoon. Heat up the frying pan over medium heat. When it is hot, add marsala wine to pan. When bubbling, add the mushrooms top side down. Cover mushrooms. Periodically check the mushrooms to make sure they aren't burning. If the pan gets dry, add more Marsala wine.
Cook the top side of the mushrooms for about 4 minutes. Flip and cook the underside until the mushrooms puncture easily, about 6 minutes.
When mushrooms are done, remove cranberry sauce and the bean mixture from the heat. Place mushrooms, top side down. Spoon in some of the bean/leek/walnut mixture. Top with the vegan Gorgonzola. Spoon on the sauce.
Enjoy!