Heat a large pan over low heat and melt the butter with a drizzle of olive oil.

Add the sliced onions and cook slowly over low heat, stirring often. This process takes time, but slowly cooking the onions allows them to caramelize and develop deep flavor.

Once the onions soften and begin to caramelize, add the diced garlic, salt, sugar, mixed herbs, and paprika.

Pour in the white wine to deglaze the pan and scrape up any browned bits. Let it cook down until most of the wine evaporates.

Add the cream, chicken stock cube, and water. Let the mixture simmer over medium heat until creamy and slightly thickened.

Stir in the parmesan cheese and allow it to melt into the sauce. Taste and adjust seasoning if needed.

Season the skirt steak with salt, black pepper, and garlic powder.

Heat a skillet over medium-high heat and add olive oil.

Add the steak and cook until nicely seared. During the final minute of cooking, add minced garlic to the pan and cook it with the steak until fragrant.

Remove the steak from the pan and let it rest for several minutes.

Slice the steak thinly against the grain.

Slice the ciabatta bread and toast lightly if desired.

Add the sliced steak to the bread and place provolone cheese over the top.

Spoon the creamy caramelized onions over the steak.

Add fresh arugula and close the sandwich.

Serve immediately while warm.