For one marvelous sandwich:
1 Tablespoon olive oil or butter or a combination
3 mushrooms, cut in thirds, then 1/4″ slices
about 2 Tablespoons of chopped onion or shallot
1 large handful baby arugula
about 10 large basil leaves, chiffonade
salt, to taste
1/2 Tillamook sharp cheddar Farmstyle (thick) slice
3 thin slices provolone
1 teaspoon Dijon mustard
soft butter
2 slices Trader Joe’s Sandwich Sourdough Bread or Sumano’s Watsonville Sourdough Loaf
In a small skillet over medium heat, warm the butter and/or olive oil. When hot, add the onions, and a bit of salt, and saute until they begin to soften.
Meanwhile, heat a large cast-iron skillet over medium heat. Butter one side of one slice of the bread. Spread mustard on the other side, and place it butter-side-down in the large skillet. Break up the cheddar cheese into a few pieces and distribute it evenly on the mustard-side of the bread. Cover with 1.5 slices of the thin provolone.
Push the onions to one side of the small skillet. In the now-empty side, add a touch more oil or butter if needed, and then the mushrooms. Salt them, and let them cook until they are as done as you like. Stir together with the onions, then place the arugula and basil on top and cover. Let the greens steam for about a minute, then remove the lid and stir all together, adding a bit more salt if needed, and let cook for about 30 seconds more.
Pick up the small skillet and carefully transfer the mushrooms, onions, and greens onto the melted-cheese-covered bread in the large skillet. Top with the other 1.5 slices of provolone. Butter one side of the remaining piece of bread and put it on top of the sandwich, butter-side up.
Check the bottom of the sandwich – it is probably perfectly browned now. Using a wide spatula, and holding the sandwich together a bit with your other hand, flip the sandwich over to brown the other side and melt the cheese on that side.
When the second side is nicely browned, remove the sandwich to a cutting board. Cut your sandwich as you like – I like to do 4 vertical strips.
Serve with fruit.