Wash and dry produce.

Trim and thinly slice scallions, separating whites from greens.

Heat a drizzle of oil in a large, preferably nonstick, pan over medium-high heat. Add scallion whites, beef*, garlic powder, a pinch of salt, and pepper. Cook, breaking up meat into pieces, until beef is cooked through, 4-6 minutes.

Taste and season with salt and pepper if desired. Carefully drain any excess grease from pan. TIP: Blot excess grease from pan using a paper towel and tongs.

Meanwhile, quarter lemon. Dry lettuce thoroughly. Trim and discard root end from lettuce; chop into bite-size pieces. Halve tomato lengthwise; slice into ¼-inch-thick half-moons.

In a large bowl, whisk together 2 TBSP olive oil, ½ tsp sugar, juice from half the lemon, and a pinch of salt and pepper (4 TBSP olive oil and 1 tsp sugar for 4 servings). 

Add lettuce, tomato, and scallion greens to bowl with dressing; toss to combine. Taste and season with salt and pepper if desired. 

Wrap pitas in damp paper towels; microwave until warm and pliable, 30-60 seconds. 

Halve pitas; gently pull apart to create pockets.

Divide pitas between plates. Fill with beef and as much harissa aioli and salad as you like. Serve with remaining lemon wedges and any remaining salad on the side.