This is the vegan variant of the base of Polands most famous dish, the zapiekanka.
In Cracow you get the best ones in the jewish district Kazimierz at plac Nowy, dozens of mini bars strung together in a circular rotunda where you can choose from different toppings like chives, ananas, corn, pickled cucumbers and various sauces like ketchup, piri piri, cocktail sauce or mayonnaise.
The newest creation I saw there was a maki toping, which reminds my to cover my next ones with some avocado-cucumber makis.
Only the sky is the limit, you can use onions with garlic instead of the mushrooms as base and fold in halved cocktail tomatoes and marinated tofu into the sauce and cover with some fresh basil after backing.
Serves 4
- 500 g button mushrooms
- 6 T olive oil
- 500 ml soy milk
- 1 T potato starch
- 3 leaves of leek
- 4 french rolls
- Salt and pepper
Cure the button mushrooms and cut into quarters. Sear in a big pan in 2 T olive oil till they get a nice brown color.
Only now salt them, as they immediately will give off their juices.
Dissolve the starch in some soy milk, then stir in into the mushrooms with the remainder.
Stir till you get a nice thick sauce. Remove from the stove.
Chop the leek into fine slices and fold into the sauce. Season with salt and pepper.
Cut the rolls in half and brush the cut surface with the olive oil. Lay down with this side in a hot pan and roast for one or two minutes.
Spread the french rolls in a backing dish and cover with the mushroom sauce.
Grate in the oven for 10 minutes at 170°C/340°F.
Serve fresh from the oven.
My grateful thanks go to 
Bon appétit,
Miron