Classic Ciabatta Steak Sandwich with Caramelized Onions
A flavorful grilled steak sandwich on toasted ciabatta bread layered with sweet caramelized onions, melted provolone cheese, and a tangy horseradish mayo. Perfect for a satisfying American lunch.
Ingredients
Check ingredients as you go.
- Bread and Spread
- Steak
- Steak and Bread
- Seasoning
- Caramelized Onions
- Cheese
- Spread
- Garnish
Let’s make it
Steak
Preheat your grill or grill pan over medium-high heat. Brush the steak with 1 tablespoon olive oil and season both sides generously with salt and black pepper.
Steak
Place the steak on the grill and cook for about 4 minutes per side for medium-rare, or until desired doneness. Remove from grill and let rest for 5 minutes.
Caramelized Onions
Meanwhile, melt the butter in a skillet over medium heat. Add the thinly sliced onions and cook, stirring occasionally, for about 10 minutes until soft and golden. Stir in brown sugar and continue to cook for another 5 minutes to caramelize. Remove from heat.
Bread and Steak Assembly
Slice the rested steak thinly against the grain. Slice the ciabatta bread and brush the cut sides lightly with the remaining 1 tablespoon olive oil. Grill the bread slices cut side down until toasted and marked, about 1-2 minutes.
Spread
In a small bowl, mix mayonnaise with prepared horseradish until smooth.
Sandwich Assembly
Spread the horseradish mayo generously on both sides of the toasted ciabatta. Layer the bottom half with sliced steak, then caramelized onions, and top with provolone cheese slices. Add lettuce if using for freshness and crunch.
Final Step
Close the sandwich with the top half of the bread, press gently, then slice in half. Serve immediately while warm.
Tips & notes
For best results, rest the steak before slicing to retain juices and ensure tenderness. Use a serrated knife to slice the ciabatta bread to maintain its crusty texture. Caramelizing onions slowly over medium heat develops deep flavor; if short on time, increase heat slightly but stir frequently to avoid burning.
Saving it for later
Store leftover steak and caramelized onions separately in airtight containers in the refrigerator. Ciabatta bread should be kept in a paper bag at room temperature for up to 2 days or frozen if longer storage is needed. Use steak leftovers within 3 days.
Reheating
Reheat the steak slices gently in a skillet over medium-low heat just until warm to avoid drying out. Warm caramelized onions separately on low heat if desired. Toast the bread again briefly and assemble sandwiches fresh to retain texture and flavor.
