Smoky Smash Burger Lettuce Wraps with Pickled Onion

Steps

1. Quick-pickle first: stir the cider vinegar, sugar and one quarter of the salt in a small bowl until dissolved, add the red onion, and let stand at least 20 minutes while you prepare everything else.
2. Make the sauce: stir the Greek yogurt, hot sauce and lime juice together in a small bowl and chill until serving.
3. Mix the paprika, garlic powder, cumin, black pepper and the remaining three quarters of the salt in a small dish to make the spice rub.
4. Divide the ground beef into 8 loose balls of equal size without packing them; keep them cold.
5. Wash and dry the romaine leaves and slice the tomato so the toppings are ready before cooking.
6. Heat a large cast-iron skillet over medium-high heat until very hot, then brush it with the canola oil.
7. Place 4 beef balls in the skillet, smash each flat with a sturdy spatula, and sprinkle the tops with half of the spice rub.
8. Cook about 2 minutes until the edges are deeply browned, scrape up and flip, and cook 1 minute more until the patties reach 160°F (71°C); transfer to a plate.
9. Repeat with the remaining 4 beef balls and the remaining half of the spice rub.
10. Drain the pickled red onion. Stack 2 romaine leaves per wrap, add 2 patties, then the tomato slices, pickled red onion and a spoonful of the yogurt sauce, and wrap the leaves around to serve.