Steak Sandwich with Crispy Fried Onions, Melty Cheese and Hot Mayo

Melty cheese, crispy fried onions, meltingly tender steak, and spicy mayo; this sandwich has it all!

Tossing the onions in a bit of cornstarch prior to frying helps them crisp up a little faster, adding a bit of crunch to this slightly spicy steak sandwich. Add as much or as little cheese as you want, or as much or as little hot sauce to the mayonnaise as you want. If you prefer your bread on the crisper side, pop it in the toaster prior to putting the steak sandwich in the oven.

This is a great, filling steak sandwich that’s perfect for a lazy weeknight meal or a slightly decadent lunch! When we make steaks on the grill or in the cast iron pan at home, I like to make a little extra and slip it into the fridge. That way, this sandwich can come together even faster.

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Cheesy Fried Onion Steak Sandwich with Hot Mayo



for the steak:

  • 1 6-8 oz rib eye or sirloin steak (, cooked medium rare to medium)
  • 1 tablespoon olive oil
  • salt and pepper (, to taste)

for the fried onions:

  • 1 small onion (, thinly sliced (about 1/2 cup))
  • 1 teaspoon cornstarch
  • 1/2 teaspoon olive oil

for the mayonnaise:

  • 1 teaspoon hot sauce
  • 3 tablespoons mayonnaise

for the sandwich:

  • 2 slices crusty bread
  • 24 slices white cheddar cheese ((about 4 oz))


make the steak:

  1. Preheat the oven to 450*F.
  2. In a cast iron pan or nonstick, ovenproof skillet, heat the olive oil until shimmering. Sprinkle the steak evenly on both sides with salt and pepper, and add to the pan. Sear each side of the steak until a golden brown crust appears, about 3-4 minutes a side. Finish the steak in the oven to the desired stage of doneness, about 3-5 minutes. Remove and let rest until ready to slice.

Make the onions:

  1. In a cast iron pan or nonstick skillet, heat the olive oil until shimmering.
  2. Add the onions and cornstarch to a small bowl and toss to coat.
  3. Fry the onions in the olive oil until cooked through and crispy, about 4-5 minutes.
  4. Remove and let rest until cool enough to handle.

Make the mayonnaise:

  1. Mix together the hot sauce and mayonnaise in a small bowl. Any mayo leftover will keep in the fridge, tightly covered, for up to one month.

Make the sandwich:

  1. Layer the mayo on both sides of the bread, top with steak and fried onions. Layer with cheese.
  2. Line a sheet pan with aluminum foil and bake the sandwich, open faced, until the cheese melts and is bubbly.

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