Heat oven to 400 degrees.
Place green beans, orange peppers and red onion on a baking sheet.
Place zucchini and squash on another baking sheet.
Drizzle vegetables on both baking sheets with olive oil and whole-grain mustard.
Season all the vegetables with salt and pepper.
Roast in the oven for 12 minutes.
Remove from the oven and set aside.
While the vegetables are roasting, season the steak with Italian seasoning, salt and pepper.
In a small bowl, combine oregano, garlic, olive oil, vinegar, and 1/2 tablespoon of whole-grain mustard. Whisk until combined. Set aside.
Heat a grill pan or skillet with some olive oil. Fry the steaks until the desired doneness. If you have a meat thermometer, grill the steaks at 145 degrees for rare, 155 degrees for medium rare and 165 degrees for well done.
Remove the steaks from the grill and allow them to rest for 5 minutes before slicing.
To build the salad, place some romaine lettuce and endive into bowls. Toss in some grape tomatoes.
Place some roasted vegetables on top of the greens. Arrange them side by side rather for a pretty presentation.
Arrange steak slices on top.
Drizzle with the dressing.