Steak Sandwich with Caramelized Onions

This steak sandwich is simple but packed with flavor — seared steak, sweet caramelized onions, peppery arugula, and a tangy horseradish-balsamic sauce.

Choosing the Steak

You don’t need a fancy cut, but it should be something tender. Sirloin, ribeye, or flank steak all work well. I used fillet cap steak, which I find very flavorful and tender. Just season it well, sear it hot, and let it rest before slicing thin against the grain. Go for about 150g per person, or more if you’re hungry.

Choosing the Bread

Use bread with a bit of structure so it holds up to the sauce and steak. A crusty roll, ciabatta, or sliced sourdough works great. You can toast it if you want extra crunch, but it’s optional — just don’t use anything too soft or thin, or it’ll fall apart.

Steak Sandwich with Caramelized Onions

Recipe by HenriCourse: Lunch, DinnerDifficulty: Medium

Servings

2

servings

Prep time

10

minutes

Cooking time

30

minutes

Ingredients

• 300g steak (150g per person — adjust to your liking)

• Bread of your choice

• 50g arugula/rocket/rucola

• Salt & pepper, to taste

• Caramelized onions

• 2 large onions, thinly sliced

• 1 tbsp butter

• ½ tsp salt

• (Optional) Dash of vermouth

• Sauce

• 4 tbsp Mayo

• 1 tbsp balsamic vinegar

• 1 tsp horseradish paste

• 1 tbsp lemon juice

• Salt & pepper, to taste

Directions

• Prepare the sauce by mixing all the ingredients together. If you have the time, salt the steak at least one hour before cooking.
• In a skillet over medium-low heat, cook the sliced onions with butter and salt until caramelized — this usually takes 15–20 minutes for this amount.
• (Optional) Once the onions are caramelized, add a splash of vermouth (or another liquor) and cook until the liquid has mostly evaporated.
• Cook the steak to your liking, then let it rest and slice thinly.
• (Optional) Toast the bread.
• Assemble: Spread the sauce on both halves of the bread, layer with arugula, sliced steak, and caramelized onions.

This sandwich is great as a weekend lunch or even a casual dinner. It’s filling, easy to tweak, and works well with leftover steak too. If you want to change it up, you could add a slice of cheese or swap the arugula for other greens.