Steak Sandwich

Ingredients

Melt the butter in a large skillet over medium-low heat. Add the sliced onion and stir. Cover with a lid and cook for 20 minutes, stirring occasionally. Remove the lid and stir in the sugar, salt and pepper. Cook for a further 10 minutes, until brown a bit and caramelize.

Pat the steak dry with paper towels. Generously season it on both sides with salt and pepper. Using a grill or a skillet, cook the steaks to your preferred temperature and let them rest for 10 minutes.

Slice the steak into thin strips against the grain. Cut the ciabatta buns in half horizontally.
Spread a tablespoon of pesto on each bottom half of the buns, then top with ½ cup each of baby arugula, followed by steak slices, caramelized onions and tomatoes. Spread mustard and mayo on the top bun then place on top.

Slowly cook the onions. For the most flavorful caramelized onions, you have to cook them slowly. Turn up the heat and you’re going to have fried onions not caramelized.
Don’t overcook the meat. No problem tastewise and totally your preference if you want your meat well done, but you can still overcook it. So make sure to stop cooking it before it gets too tough.
Make and eat. For the yummiest steak sandwich, eat it right after it’s grilled and assembled. Leftovers are tasty too, but fresh is always best.
Assembled sandwiches will keep in the fridge for up to 3 days. And a leftover cold steak sandwich is delicious. However, if you would like to reheat, you can remove the steak with the caramelized onions from the sandwich and pop them in the microwave for a few minutes on medium to warm them up.