Place the asparagus on a large cutting board and line up the ends with your hands, then use a chef’s knife to cut about 1 to 2 inches off the tough bottoms so only tender stalks remain.​

Rinse the trimmed asparagus under cool running water in the sink, then dry the spears completely with a clean kitchen towel or paper towels so they char well on the grill instead of steaming.​

Lay the dry asparagus in a single layer on a rimmed baking sheet or large tray and spread the spears out with your hands so they are easy to coat.​

Use a measuring spoon to drizzle 1 tbsp olive oil and 1 tbsp lemon juice over the asparagus, then sprinkle 1 tbsp za’atar, ½ tsp lemon zest, ½ tsp kosher salt, and ¼ tsp black pepper on top and toss everything with your hands until every spear looks evenly covered with oil and seasoning.​

Add ½ cup Greek yogurt to a small mixing bowl, then pour in 1 tbsp lemon juice and 1 tsp olive oil with measuring spoons.

Sprinkle ¼ tsp kosher salt and ⅛ tsp black pepper over the yogurt, then whisk with a whisk until the sauce looks smooth and just thin enough to drizzle from a spoon.​

Preheat the grill to medium-high heat, around 400°F, with the lid closed, using the grill controls or vents and the built-in thermometer if your grill has one.​

Scrub the hot grates with a grill brush, then oil the grates by gripping a folded paper towel with tongs, dipping it in a little oil, and rubbing it over the bars so the asparagus does not stick.​

Use tongs to lay the seasoned asparagus across the grill grates so the spears sit perpendicular to the bars in a single layer, which keeps them from falling through.​

Close the lid and grill for 4 minutes, then open the lid and use tongs to turn each spear so a new side faces the grates and starts to char.​

Grill for 4 more minutes with the lid closed, then check one spear with tongs; the asparagus should bend slightly, show dark char marks and some blackened edges, and still look bright green inside.​

Use tongs to transfer the charred asparagus from the grill back to the baking sheet or straight onto a serving platter, keeping the spears lined up neatly.​

Spoon the lemon yogurt over the hot asparagus in thin lines or small dollops, using the spoon to drizzle, then sprinkle a light extra pinch of za’atar over the top for color and aroma before serving.​