Spicy, cheesy Salisbury steak inside-out pizza sandwich

Ingredients

• 450 grams bread flour (3 3/4 cups or all-purpose flour)
• 12 grams sugar (1 tablespoon)
• 11 grams salt (2 teaspoons)
• 3 grams instant yeast (1 teaspoon)
• 284 grams water (1 1/4 cups)
• 12 grams vegetable oil (1 tablespoon)
• 1 ⁄ 4 cup gochugaru, coarse flakes
• 1 1 ⁄ 2 tablespoons gochujang
• 2 1 ⁄ 2 tablespoons corn syrup, rice syrup, or honey
• 1 1 ⁄ 2 tablespoons vegetable oil
• 1 1 ⁄ 2 teaspoons soy sauce
• 3 garlic cloves, minced
• 1 teaspoon ginger, minced
• 1 pound ground beef (80/20 or 85/15 - either is fine)
• 2 tablespoons ketchup
• 1 tablespoon hoisin sauce
• 1 whole egg, beaten
• 1 ⁄ 2 cup bread crumbs
• 3 tablespoons salted butter
• 8 ounces sliced button mushrooms (about 10 or 12 mushrooms)
• 1 cup diced onion
• 2 tablespoons all-purpose flour
• 3 cups beef broth
• 1 tablespoon ketchup
• 2 to 3 tablespoons fire paste (from above)
• 1 teaspoon cornstarch
• 1 tablespoon water
• salt
• pepper
• 1 seven-inch dough round, per sandwich (from above)
• 1 ⁄ 4 to 1 ⁄ 2 cup spicy mushroom gravy, per sandwich (from above)
• 1 half-pound salisbury steak patty (from above)
• 2 to 3 ounces shredded cheese (I used fontina, but mozzarella works great)
• cilantro (for garnish)