Adjust rack to middle position and preheat oven to 425 degrees. Pat steaks dry with a paper towel, and lightly coat all sides with salt and pepper. Set aside to rest.
Toss butternut squash on a baking sheet with a drizzle of olive oil, and a pinch of salt and pepper. Roast in oven until tender and browned, about 25-30 minutes, tossing halfway through.
Right before you take the butternut squash out to toss, preheat a drizzle of olive oil in a large nonstick pan over medium-high heat.
Using an oven mitt, remove pan from oven and place on a backing rack after the squash has roasted for about 15 minutes. Using tongs, toss green beans on a baking sheet with a drizzle of oil and a pinch of salt and pepper. Return pan to oven, to toast roast, tossing halfway through, until browned and slightly crisp, 12-15 minutes.
Add steak to the preheated pan and cook until nicely browned and seared on first side, 3-6 minutes. Use tongs to turn the steaks and lower heat to medium. Add 1 tsp Herbes de Provence and 2 TBSP butter to pan and carefully tilt pan toward you. Continually baste steak with butter and Herbes de Provence using a spoon, until it reaches desired doneness, 4-7 minutes more.
Transfer steak to a plate and tent loosely with foil, allowing to rest while your vegetables finish roasting.
Once your vegetables are finished roasting, plate them along with your steak. Drizzle any remaining steak juices and butter from the pan over the steaks.