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Steak, Mushroom & Swiss Open Sandwich
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5 from 2 votes

Steak, Mushroom & Swiss Open Sandwich

Prep Time15 minutes
Cook Time40 minutes
Total Time55 minutes
Course: Main Course
Cuisine: American
Servings: 4

Ingredients

  • 1 lb New York beef steak (about 3/4 inch thick)
  • 2 tablespoons butter
  • 1 lb thinly sliced mushrooms
  • 2 garlic cloves, minced
  • a good pinch of salt & freshly ground pepper
  • 1 tablespoon olive oil, plus extra for brushing on steaks
  • 2 cups thinly sliced onion (about 2 large onions)
  • 1/4 cup red wine vinegar
  • 1/4 cup packed brown sugar
  • 2 cups grated Swiss cheese
  • 1/2 cup whole egg mayonnaise
  • 2 tablespoons yellow mustard
  • 8 slices artisan bread
  • baby spinach leaves, to serve

Instructions

  • Remove steak from the fridge 20 to 30 minutes before cooking. 
  • Melt butter in a large frying pan over medium-high heat. Add mushrooms & garlic & cook, stirring occasionally, for 5 minutes or until mushrooms are softened. Remove from the pan to a bowl & set aside. 
  • Heat 1 tablespoon of oil in a large frying pan over medium heat (I use the same pan I cooked the mushrooms in). Cook onion, stirring occasionally, for10 minutes, or until softened. Add vinegar, sugar, salt & pepper. Cook, stirring occasionally for 5 to 7 minutes or until sugar is dissolved & mixture is thick & jammy. 
  • Brush or rub both sides of each steak with a little oil; sprinkle with salt & pepper. Heat griddle pan or barbecue grill over medium-high heat. Cook steak for 5 minutes on one side. Turn & cook 3 minutes or until cooked to your liking (135-140F for medium-rare). The thickness of the steak will further determine the cook time. Let stand for 5 minutes then cut into thin slices; set aside.
  • Combine cheese, mayonnaise & mustard in a small bowl; set aside. 
  • Place bread slices in a single layer on a foil-lined baking sheet. Toast in 375F oven for 15minutes or until they’re starting to turn golden & crisp. 
  • Divide onion mixture between each piece of toast & spread to cover. Arrange steak over onion. Top with mushrooms. Dollop the cheese mixture over the mushrooms. Place pan under hot broiler (grill), 6-inches away from the heat source. Cook for 3 minutes or until cheese mixture is melted & bubbling. 
  • Serve with spinach leaves drizzled in a little olive oil & red wine vinegar, if desired.