Can I use a different cut of steak for this sandwich?
Ribeye is ideal for its tenderness and marbling when shaved thin, but flank steak or sirloin can substitute. Freeze the steak for 1-2 hours before slicing to get clean, thin shavings.
How do I make the cheese sauce from scratch?
Melt butter in a saucepan, whisk in flour to form a roux, gradually add milk or cream while stirring, then fold in shredded sharp cheddar or provolone. Season with salt, pepper, and a pinch of garlic powder.
What's the best way to caramelize onions?
Slice onions thinly, cook in olive oil or butter over medium heat for 30-40 minutes, stirring occasionally. They should turn deep golden brown and develop a sweet, jammy texture.
Can I make this sandwich ahead?
Assemble the sandwich just before serving to keep the roll from becoming soggy. You can caramelize onions and make cheese sauce up to 2 days ahead and reheat gently.
What type of sesame seed roll works best?
Use a thick, sturdy hero roll or sub roll that can hold the moisture from the cheese sauce and onions without falling apart. Italian or bakery-style rolls work better than soft sandwich bread.