Position one rack in the middle of the oven and another 6 inches under the broiler heat source, and preheat to 400 degrees. In a shallow medium bowl, combine the yogurt, lemon juice and ½ teaspoon of cumin; season to taste with salt. Liberally season the salmon with salt and pepper, then add it to the bowl and coat the fish with the yogurt mixture.

On a larges sheet pan, toss the broccolini and lemon slices with the olive oil, remaining ½ teaspoon cumin, crushed red pepper, salt and pepper until all the broccolini pieces have a light sheen to them. (You can pick seeds out of the lemons before or after roasting.) Push the vegetables to the side so the salmon has direct contact with the pan. Place the salmon in the center, skinned side down.

Roast on the middle rack for about 10 minutes, or until the broccolini and lemon are lightly browned at the edges. Using tongs, flip the broccolini. Sprinkle the za’atar over the salmon, then return to the oven (rotating the baking sheet front to back) and roast for an additional 6 minutes, until the salmon is opaque.

Turn on the broiler, move the baking sheet to the upper rack, and broil for 2 minutes more for medium-rare. Transfer the baking sheet to a counter and let the salmon rest for 2 minutes.

Divide the salmon, broccolini and lemon rounds on plates. Garnish with parsley, if using, and serve.