📖 Instructions

1. First things first, let's get that steak ready. Pat it dry with paper towels—this helps it sear beautifully. Season generously with salt and pepper. I like to use freshly cracked pepper; it makes a difference, trust me!
2. Heat a large skillet over medium-high heat. Add a tablespoon or two of olive oil (or your favorite cooking oil). Once hot, add the steak and sear for about 2-3 minutes per side, until a nice crust forms. Don't overcrowd the pan; work in batches if needed.
3. After searing, reduce the heat to medium and continue cooking the steak to your desired doneness. Remember, using a meat thermometer is your best friend here for perfect results. Once cooked, remove the steak from the skillet and let it rest for a few minutes before slicing thinly against the grain.
4. While the steak rests, let's prep the other ingredients. Thinly slice the onions and bell peppers. If you're using mushrooms, slice those too. Trust me, this is so much tastier than using pre-sliced stuff.
5. In the same skillet (no need to wash it!), add a little more oil if needed and sauté the onions and peppers until they're softened and slightly caramelized—about 5-7 minutes. If using mushrooms, add them in the last couple of minutes of cooking.
6. Now, for the cheese sauce! In a small saucepan, melt the butter over low heat. Whisk in the flour until smooth, making a roux. Gradually whisk in the milk, stirring constantly until the sauce thickens. Add the cheese, stirring until melted and smooth. Season with salt and pepper to taste. Remember, this sauce is life!
7. Lightly toast your sub rolls (optional, but highly recommended). Spread a thin layer of mayonnaise or your favorite sauce on both halves of the roll.
8. Layer the thinly sliced steak on the bottom half of the roll, followed by the sautéed vegetables and a generous amount of the amazing cheese sauce. Trust me, don't skimp on the sauce!
9. Top with the other half of the roll and there you have it. Your incredible Steak & Cheese Sub! For an extra crispy finish, you can broil it in a toaster oven for a minute or two to get that gorgeous golden-brown finish. But be careful not to burn it!