Steak Sandwich with Grilled Onions

A luscious Steak Sandwich piled high with grilled onions, a spicy mustard mayo, and arugula on ciabatta bread. A meal all on its own.
This Steak Sandwich with Grilled Onions recipe is based on an older Ina Garten recipe with several tweaks by me. I’ve always cooked so many of her recipes because, well, they’re just downright good. This one is also a meat lover’s delight.

If there’s a meat eater that you want in your life, make them this sandwich and they’ll follow you anywhere. If there’s already a meat lover in your life, make them this sandwich and they’ll think they’ve died and gone to heaven.
BeeBop really loves it (and so do I!). Just be sure to have plenty of napkins on hand when you serve it.
How to Make Steak Sandwich with Grilled Onions
Season the steak liberally with salt and pepper on both sides.

Heat 1 tablespoon of olive oil in a medium saute pan over high heat until it’s almost smoking, then sear the steak for about a minute.

Turn it over and sear the other side for about a minute. The pan should be very hot while you’re searing. I used an iron skillet because it gets really hot and holds the heat for a long time.
Reduce the heat to low and cook the steak for about 7 to 10 minutes for rare, up to 15 minutes for well done.
When the cooking time is finished, remove it to a plate and cover tightly with foil. Allow the steak to rest for 10 minutes while you cook the onions.
Use the same pan without cleaning it out. Just leave all that good brown stuff in there. Heat 1 1/2 tablespoons of olive oil over medium heat.

Add the onion and thyme and saute for 10 minutes.

Stir the onions often making sure you turn them over frequently so they all cook evenly and turn a golden, caramel brown.

To assemble the sandwiches, first slice the steak on an angle.

And if you can resist popping that one little piece on the end into your mouth, you’re a better woman than I am. Around here that’s called the “Cook’s Treat.”

Spread Mustard Mayo on top and bottom of the bun. Or bread. Or baguette, or whatever you’re using.

Place a layer of steak strips on the bottom of the bun, sprinkle with salt and pepper.

Top with the caramelized onions.

Place baby arugula on top of the onions and cover the sandwich with the top half of the bun.

Just look at that thing. A meat lover’s dream!
🧾 More Recipes You’ll Like
- Mediterranean Pressed Sandwich
- Tuna Melt
- Meatball Subs
- Hot Roast Beef Sandwiches with Horseradish Cream
- Tea Sandwiches Three Ways
- Chicken, Bacon & Mushroom Sandwich
- Grilled Chicken, Apple, and Gouda Sandwich
HAVE YOU TRIED THIS RECIPE?
I’d LOVE to know what you thought!
Leave a rating below in the comments and let me know how you liked it!
WE’RE ON FACEBOOK, TOO!
If you’d like to hang out with lots of other Southern Comfort Food lovers, make sure to join my FREE PRIVATE Facebook group.

Steak Sandwich with Grilled Onions
Ingredients
- 12 ounces New York strip steak
- Kosher salt
- Black pepper
- Olive oil
- 2 yellow onions sliced in rings
- ½ teaspoon fresh thyme leaves
- 2 sub buns a loaf of French bread, or other rustic bread
- ½ cup baby arugula
For the Mustard Mayo:
- ⅓ cup mayonnaise
- 2 tablespoons Dijon mustard
- 1 tablespoon whole-grain mustard
- 2 tablespoons sour cream
- ⅛ teaspoon Kosher salt
Instructions
Make the Mustard Mayo:
- Stir all ingredients together in a small bowl. Set aside.
For the Sandwiches:
- Season the steak liberally with salt and pepper on both sides.
- Heat 1 tablespoon of olive oil in a medium saute pan over high heat until it's almost smoking, then sear the steak on each side for 1 minute.
- Reduce the heat to low and cook the steak for about 7 to 10 minutes for rare, up to 15 minutes for well done. Remove to a plate, cover tightly with foil, and allow to sit for 10 minutes while you cook the onions.
- Using the same pan, heat 1 1/2 tablespoons of olive oil over medium heat. Add the onion and thyme and saute for 10 minutes, until the onions are brown and caramelized, stirring occasionally.
- To assemble the sandwiches, spread Mustard Mayo on top and bottom of the bun. Place a layer of steak strips on the bottom of the bun, sprinkle with salt and pepper and top with the caramelized onions. Place baby arugula on top of the onions and cover the sandwich with the top half of the bun.
Nutrition Information
Nutrition information is calculated by software based on the ingredients in each recipe. It is an estimate only and is provided for informational purposes. You should consult your health care provider or a registered dietitian if precise nutrition calculations are needed for health reasons.
Have mercy……
You had me when I saw the word “steak”.