Preheat the oven to 400 degrees F.
Combine broth and salt in a small pot and bring to a boil over high heat.
Once boiling, mix in the couscous, cover the pot and reduce the heat to low. Simmer for 10-12 minutes, mixing occasionally. Turn off the heat once ready.
While the couscous simmers, roast the zucchini. On a nonstick or parchment-lined pan, toss the zucchini and yellow squash with oil, salt and pepper. Spread into an even layer and bake for 25-35 minutes until golden and cooked through, mixing halfway through.
Once the couscous is cooked, mix in the scallions and lemon juice. Set aside.
Pat steak dry with a paper towel and season both sides with salt and pepper.
Heat a heavy skillet (ideally cast iron) over medium-high heat and add the oil.
Once hot, place the steak into the pan and sear for 6-8 minutes per side until super crispy on the outside and cooked to your desired doneness on the inside. You can use an instant read thermometer to check for doneness too (135°F medium-rare, 145°F medium).
Transfer cooked steak to a cutting board to cool slightly, then slice against the grain into thin strips.
Whisk together the sauce ingredients in a medium bowl.
Assemble each bowl with couscous, roasted squash, sliced steak, cherry tomatoes and red onion. Drizzle with the sauce and top with fresh mint for garnish.