1 bunch broccolini, ends trimmed, thick stalks split lengthwise, or broccoli, stalks trimmed and cut into bite-size pieces
1 pint grape tomatoes, halved (about 2 cups)
1 small red onion, peeled, quartered and cut into 2-inch wedges
1 lemon, 1/2 cut into thin rounds and the remaining 1/2 left intact, for serving
3 tablespoons olive oil, plus more for serving
1 teaspoon ground cumin
½ teaspoon red-pepper flakes
Kosher salt and black pepper
2 (6- to 8-ounce) blocks feta, cut into 1-inch slices
Cooked orzo or farro, for serving
½ cup fresh basil or cilantro leaves and fine stems, roughly chopped (optional)
Heat the oven to 400 degrees with a rack set in the lower third. On a sheet pan, combine the broccolini, tomatoes, onion and lemon slices with the olive oil and toss. Add cumin and red-pepper flakes, season with salt and pepper, and toss again until evenly coated. Nestle the feta slices into the vegetables. (It’s OK if they break apart a little.)
Roast 15 to 20 minutes, stirring halfway through but leaving the feta in place, until the broccolini is charred at the tips, the stems are easily pierced with a fork and the tomato skins start to blister and break down.
Serve over orzo or farro. Drizzle with olive oil and serve with the remaining lemon half for squeezing. Top with fresh herbs, if using.