Steak Mushroom Ciabatta Sandwich with Caramelized Red Onions & Rocket

Serves: 2

Prep time: 20-25 minutes 
Cook time: 25-30 minutes

• 1 (8-ounce) Giorgio® Sliced Mushroom Grill Pack with Steak Seasoning
• 2 ciabatta rolls or 1 ciabatta loaf, sliced in half lengthwise
• 1 sirloin steak (8–12 oz)
• ½ tablespoon cooking oil
• 1 tablespoon butter, for cooking steak
• 1–2 garlic cloves, lightly crushed
• A few sprigs fresh thyme

For the Caramelized Red Onions:

• 1 medium red onion, thinly sliced
• 1 tablespoon cooking oil
• 1 tablespoon brown sugar
• 1 tablespoon balsamic vinegar
• Salt, to taste

For the Mustard Mayo:

• 3 tablespoons mayonnaise
• 1 tablespoon whole-grain mustard
• 1–2 tablespoons fresh chives, finely chopped
• 2 handfuls arugula (rocket)

FOR COOKING THE MUSHROOMS

Grill Instructions

1. Preheat grill to 450°F.
2. Remove cardboard sleeve, plastic wrap, and seasoning packet.
3. Add 2 tablespoons of cooking oil to mushrooms.
4. Sprinkle seasoning over mushrooms and toss to coat evenly.
5. Place tray directly on grill.
6. Cook for 25–30 minutes, stirring occasionally, until tender and fully cooked.

Oven Instructions

1. Preheat oven to 450°F.
2. Remove cardboard sleeve, plastic wrap, and seasoning packet.
3. Add 2 tablespoons of cooking oil to mushrooms.
4. Add seasoning and toss to coat evenly.
5. Place tray in oven.
6. Roast for 25–30 minutes, stirring occasionally, until mushrooms are caramelized and cooked through.

For best results: Cook to an internal temperature of 165°F.

METHOD 

1. Heat the oil in a skillet over low/medium heat. Add the sliced red onion and a pinch of salt. Cook very gently for 20-25 minutes, stirring occasionally, until softened and lightly golden, add a splash of water if they start to catch. Once completely soft, add the brown sugar and balsamic vinegar. Continue cooking for another 5 minutes, stirring often, until the onions are jammy and caramelized. Remove from heat and set aside.
2. Pat the steak dry and rub the oil all over the steak. Season well with salt and pepper. Heat a skillet over medium-high heat. Once hot, add the steak. Press it down with a spatula to ensure even contact with the pan. Flip the steak over and add the butter along with the garlic and thyme. Cook for 2-3 minutes per side (depending on thickness and desired doneness), spooning the melted butter over the steak as it cooks. Remove from the pan and let rest for 5–10 minutes before slicing thinly.
3. Mix the mayonnaise, whole-grain mustard, and chopped chives in a small bowl until combined. Set aside.
4. Lightly toast the ciabatta in a dry pan, oven, or toaster until golden and crisp.
5. Spread the mustard mayo mixture on both sides of the toasted ciabatta. Layer arugula on the bottom half, followed by sliced steak, cooked mushrooms and a generous spoonful of caramelized onions. Top with the other half of the ciabatta.
6. Slice and serve immediately while the steak is still warm.

NOTES:

• For extra richness, add a slice of cheese (Gruyère, cheddar, or provolone work well).
• Letting the steak rest is key—this keeps it juicy when sliced.
• If you prefer more acidity, add a splash of balsamic glaze when assembling.
• Leftover caramelized onions keep well in the fridge for up to 4 days.