Ingredients for 4 servings:
2 tablespoons olive oil
2 large yellow onions, thinly sliced (about 4 cups)
2 large portobello mushroom caps, thinly sliced (about 3 cups)
11/2 teaspoons salt
1 pound trimmed flank steak, sliced as thinly as possible (preferably on a slicer)
1/2 teaspoon freshly ground black pepper
1 1/2 cups grated Pepper-Jack cheese
2 soft-crusted long baguettes, or 4 Italian-style hoagie rolls

Philly Cheese Steak

Preheat the oven to 400 degrees F.

Heat the oil in a large nonreactive sauté pan set over medium-high heat until it ripples. Add the onions and cook until soft, about 5 minutes. Add the mushrooms and 1 teaspoon of the salt and sauté until tender, about 5 minutes. Add the flank steak, the remaining 1/2 teaspoon salt, and the pepper and sauté until the meat is cooked through, about 5 minutes more.

Remove the pan from the heat. Sprinkle the cheese over the top, cover the pan, and set aside until the cheese melts, about 5 minutes.

Meanwhile, slice the baguettes lengthwise. Place, cut sides up, on a baking sheet, and toast in the oven until crisp, 4 to 5 minutes.

Fill the baguettes with the meat and cheese. Cut each into 2 portions.

Serve immediately - with or without ketchup.