Steak Sandwich With Homemade Garlic Aioli
There’s something undeniably satisfying about a really good steak sandwich—and this one hits all the right notes. Juicy, tender steak piled onto crusty, golden ciabatta, slathered with a homemade garlic aioli that’s creamy, rich, and packed with flavor. It’s the kind of sandwich that feels indulgent but is simple enough to throw together on a weeknight. My boyfriend and I are obsessed—we’ve made it more times than I can count, and every time, we eat it so fast the dinner table goes completely silent. That’s how you know it’s a winner.
Start by making the garlic aioli so the flavors have a little time to mingle while everything else comes together. In a small bowl, mix together mayo, minced garlic, Dijon mustard, lemon juice, a pinch of salt and pepper, and a drizzle of olive oil. If you’ve got fresh herbs on hand—like parsley—go ahead and chop some up and toss it in. I didn’t have any this time, and it was still delicious, so don’t stress if you’re in the same boat!
Thinly slice half an onion—white, yellow, or red all work beautifully here, so use what you have on hand. The key is slicing it nice and thin so it softens and caramelizes evenly. Add it to a pan with a drizzle of olive oil and cook low and slow, stirring occasionally. Patience is everything. Let the onions take their time until they’re soft, golden, and sweet. It’s that deep, rich flavor that takes this sandwich to the next level.
Next, tenderize your flank steak—this step is key to getting that buttery, melt-in-your-mouth texture. Place the steak between two sheets of plastic wrap or parchment paper, then use a meat mallet to gently pound it. Just enough to break down the fibers without flattening it too much. Season both sides generously with salt and pepper. Get a skillet nice and hot, then sear the steak until it’s beautifully browned on the outside and cooked to your preferred doneness. Taking the time to tenderize really makes all the difference. You will be able to bite right into the sandwich without any tough pull.
While the onions are caramelizing and the steak is doing its thing, preheat your oven to 350°F. Slice your ciabatta rolls in half and place them cut-side up on a baking sheet. Drizzle with olive oil, then sprinkle with a little garlic powder and a dash of garlic salt for that extra hit of flavor. This quick toast in the oven will give the bread a crisp, golden edge while keeping the inside soft—perfect for holding all that juicy steak and creamy aioli.
Keep an eye on those onions, giving them a stir every few minutes as they caramelize into that rich, golden goodness. Below is how mine look once good and golden. Once your steak reaches your desired internal temperature and has a gorgeous sear, pull it off the heat. I like to take mine off at 125°F for a perfect medium-rare. Just remember, the longer you cook it, the tougher it’ll get, so don’t be afraid to keep it on the rare side if that’s your vibe. Now, let the steak rest for at least 5–10 minutes before slicing. This gives the juices time to settle so every bite stays super flavorful and moist.
Now it’s time to slice and stack. Once your steak has rested, slice it thinly. To assemble, layer a generous portion of that juicy steak onto the bottom half of your golden, crispy ciabatta. Top it with a slice of provolone and pop it under the broiler for about a minute—just long enough to get that cheese perfectly melted and bubbly. Pull it out, slather your top bun with the garlic aioli. Then pile on those caramelized onions and a handful of fresh arugula for a peppery crunch. Press it all together and just try not to devour it in total silence (we never can).
And there you have it—your new go-to steak sandwich. It’s rich, flavorful, and packed with all the little touches that make it feel extra special, without being fussy. Whether you’re making it for a laid-back dinner, a date night at home, or just because you’re craving something really good, this one’s a guaranteed hit. Trust me—once you take that first bite, there’s no going back.
Steak Sandwich with Garlic Aioli & Caramelized Onions
Ingredients
For the Garlic Aioli
- 1/2 cup mayonaise
- 3 cloves garlic minced
- 1 tsp dijon mustard
- 1 tablespoon lemon juice
- salt and pepper to taste
- drizzle olive oil
- fresh parsley, chopped optional
For the Sandwich
- ½ large onion (white, yellow or red) thinly sliced
- olive oil for cooking
- 8-10 ounces flank steak
- salt and pepper to season
- 2 ciabatta rolls sliced in half
- 2 slices provolone cheese
- handful fresh arugula
Instructions
Make the Garlic Aioli
- In a small bowl, mix together the mayo, minced garlic, Dijon mustard, lemon juice, olive oil, and a pinch of salt and pepper. If using fresh parsley, stir that in too. Set aside to let the flavors develop.
Caramelize the Onions
- In a skillet over low heat, add a drizzle of olive oil and the thinly sliced onions. Stir occasionally and let them cook low and slow until soft, golden, and caramelized—this usually takes around 20 minutes.
Tenderize and Cook the Steak
- Place the flank steak between two sheets of plastic wrap or parchment paper and gently pound it with a meat mallet to tenderize. Season both sides generously with salt and pepper. Heat a skillet over medium-high heat and sear the steak until it reaches your desired doneness. For medium-rare, aim for an internal temp of 125°F. Let it rest for 5–10 minutes before slicing thinly
Prep the Ciabatta Rolls
- While the onions are caramelizing and the steak is cooking, preheat your oven to 350°F. Place the ciabatta rolls cut-side up on a baking sheet. Drizzle with olive oil and sprinkle with garlic powder and a dash of garlic salt. Toast in the oven for 5–7 minutes until lightly crisped.
Assemble the Sandwiches
- Layer the sliced steak onto the bottom halves of the toasted ciabatta. Top with provolone cheese and place under the broiler for about 1 minute, just until the cheese is melted. Remove from the oven, spread garlic aioli on the top halves of the rolls, and add the caramelized onions and a handful of arugula. Close the sandwiches and serve immediately.
Enjoy every juicy, melty, garlicky bite!
Notes
- Tenderizing the Steak: Don’t skip the tenderizing step! Using a mallet to pound the flank steak helps break down the fibers, making it more tender and easier to bite into. This is especially important for a sandwich, where you want that buttery, melt-in-your-mouth texture.
- Resting the Steak: After searing, let the steak rest for at least 5–10 minutes before slicing. This helps the juices redistribute throughout the meat, keeping it moist and flavorful.
- Onion Caramelization: Be patient when caramelizing the onions! Low and slow is the key to achieving that perfect golden color and sweet flavor. Stir occasionally to avoid burning.
- Provolone Cheese: If you prefer a different cheese, feel free to swap the provolone for something like cheddar or mozzarella—just make sure it melts well!
- Ciabatta Rolls: Toasting the ciabatta adds crunch and warmth, creating a perfect base for the juicy steak. If you prefer a softer roll, skip the oven and use fresh ciabatta. My go to and absolute favorite ciabatta are these rolls from Trader Joes!
If you’re looking for another sandwich recipe, this Crispy Chicken Sandwich is also to die for!