Chicken-of-the-woods is an astoundingly good wild mushroom, with the taste and texture of its namesake. One year, my friend Lucas and I found a large old tree, split and fallen over, with pounds of these mushrooms growing from the exposed inner trunk. We came up with this sandwich, to serve at a big fall harvest gathering, as a way to use the giant haul of mushrooms before they deteriorated. We ran tray after tray of them from under the broiler to the people mingling on the farm grounds, where they were eaten in the hand, hot and comforting in the autumn breeze.
- chicken of the woods mushrooms (probably only available at farmer's markets or very good small grocers near areas where they might be found, but you can also very much make a mushroom sandwich using this recipe with any other mushrooms)
- naturally-leavened french country bread. (the absolute best you can get, like, make a Tartine loaf yourself or find a bakery that can get close)
- extra-sharp white cheddar and gruyere, grate it all ahead of time
- dijon mustard: the best you can find
Make the basic béchamel. A knob of butter, a teaspoon of flour, a thorough whisking, biscuity smell, some whole milk or cream, until thickened. Add a chopped clove of garlic and some white pepper. Let sit on the back burner on low while you make the rest of the sandwich.
Melt lots of butter in a cast iron frying pan over medium heat. Add the brushed/pulled apart mushrooms (they will pull away all stringy, like chicken). Cover, briefly, until the moisture starts to leave the mushrooms. Uncover and cook, adjusting the pieces in the pan, until they are lightly browned on all sides.
Slice the bread, spread with mustard. Spread on some béchamel. Add a pile of the cheese mixture. Top with pieces of mushroom, then more cheese. Broil until bubbling, finishing with flaky salt and cracked pepper.