Before starting, preheat the broiler to high. Wash and dry all produce. Core, then cut pepper into 1/2-inch slices. Halve rolls. Pat steaks dry with paper towels. Sprinkle half the Italian Seasoning (use all for 4 ppl) all over steaks, then season with salt and pepper. Set aside.

Heat a large non-stick pan over medium-high heat. When hot, add 1 tbsp oil (dbl for 4 ppl), then onions and peppers. Cook, stirring occasionally, until tender-crisp, 3-4 min. Season with salt and pepper, to taste. Transfer veggies to a plate.

Add 1/2 tbsp oil (dbl for 4 ppl), then steaks to the same pan. Sear until golden-brown, 1-2 min per side. Remove the pan from heat, then transfer steaks to a foil-lined baking sheet. Broil in the middle of the oven until cooked to desired doneness, 4-7 min.**

Meanwhile, whisk together half the balsamic glaze and 1 tbsp oil (dbl for 4 ppl) in a large bowl.

Thinly slice steaks. Remove foil from the baking sheet (from step 3). Arrange rolls on the unlined sheet, cut-side up. Spread mayo over rolls. Stack steak on bottom rolls, then drizzle with remaining balsamic glaze. Arrange half the veggies on top, then sprinkle cheese over veggies. Broil in the middle of the oven until cheese melts, 1-2 min. (TIP: Keep an eye on them so they don't burn!)

Meanwhile, add spinach and remaining veggies to the bowl with dressing. Season with salt and pepper, then toss to combine. When cheese is melted, close sandwiches with top rolls. Divide sandwiches and spinach salad between plates.