Open Faced Mushroom And Onion Steakburgers

Open Faced Mushroom And Onion Steakburgers

Servings 16 Pieces
Author Melissa Sperka


  • 1 [21] inch soft french baguette
  • butter/light butter
  • garlic salt
  • 10-12 thick slices muenster/sharp cheddar/swiss cheese [your preference]
  • For the steak burgers:
  • 2 lb extra-lean ground sirloin
  • 1 large egg
  • 1 1/2 tsp steak seasoning [like Kansas City]
  • 1 Tbsp steak sauce
  • For the mushrooms & onions:
  • 8 oz sliced button/baby portabella/cremini mushrooms [your preference]
  • 1 large sweet onion thinly sliced
  • 2 tsp fresh thyme
  • 1 Tbsp balsamic vinegar
  • a couple pinches of sugar
  • salt & black pepper to taste
  • olive oil


  • Preheat the oven to 400°F and move the oven rack to the upper 1/3 of the oven. By moving the oven rack closer to the top element the meat will cook evenly without overcooking the baguette. Line a large baking sheet with parchment.
  • Slice the baguette through the middle, then cut each portion in half again making 4 pieces. Arrange side by side on the baking sheet. Butter each piece and sprinkle lightly with garlic salt. Cut the cheese slices in half.
  • Arrange half of the cheese slices over the buttered baguette reserving the other half for the top.
  • In a skillet over medium-high heat, cook the mushrooms and onions in a couple of drizzles of olive oil until golden.
  • Add the fresh thyme and season with salt and black pepper to your taste. This will take about 10-12 minutes.
  • Add a tablespoon of balsamic vinegar and a couple pinches of sugar to sweeten the onions, then cook for an additional 2 minutes. Remove from the heat and set aside to cool slightly.
  • Mix together all of the steak burger ingredients. Divide evenly between the baguettes, spreading to the edges. The meat will be thin.
  • Place into the oven and bake for 20-22 minutes depending on the thickness of the meat. Remove from the oven, place the sauteed mushrooms and onions on top, then cover with the remaining cheese.
  • Set the oven on broil, then return to the oven until the cheese melts.
  • Cut each steakburger into 4 equal pieces and serve with an assortment of flavored mayonnaise, pesto or spreads.