Remove the steak from the refrigerator about 20–30 minutes before cooking. Pat it dry, then rub both sides with olive oil. Season with salt, black pepper, most of the garlic powder, and most of the smoked paprika.

Slice the zucchini into thick rounds or lengthwise strips. Toss with a small amount of olive oil and season lightly with salt and black pepper.

Preheat an outdoor grill or grill pan over medium-high to high heat. Once hot, add the zucchini and grill for approximately 2–3 minutes per side, until tender with visible grill marks. Transfer to a plate.

Place the steak on the hot grill. Cook for approximately 4–5 minutes per side for medium-rare, depending on the thickness of the steak and your desired doneness. For food safety and consistent results, check the center with an instant-read thermometer. Transfer the cooked steak to a cutting board and let it rest for 5–10 minutes.

Meanwhile, cook the quinoa according to the package directions. Once tender and the liquid has been absorbed, fluff it gently with a fork. Season with a pinch of salt and a small drizzle of olive oil if desired.

Make the creamy sauce by combining the sour cream or Greek yogurt, Dijon mustard, remaining garlic powder, remaining smoked paprika, a pinch of salt, and optional lemon juice. Stir until smooth and creamy.

Slice the rested steak thinly against the grain.

Divide the quinoa between serving bowls. Arrange grilled zucchini and sliced steak over the quinoa, then drizzle the creamy sauce over everything. Serve the Grilled Steak Bowl while the steak and zucchini are warm.