Trim about 1/2-inch off the bottom of the broccolini stems. Rinse the broccolini under cold water and shake off the excess water.

In a large straight-sided skillet, heat the olive oil over medium-high heat until shimmering. Add the broccolini. Sauté until the broccolini is bright green and some of the stems and tips of the florets are lightly charred about 5 to 7 minutes.

Add the garlic, salt, and red pepper flakes. Continue to sauté until the garlic is fragrant, about 30 seconds.

Add the water and juice of half a lemon, cover, and cook until the broccolini is vibrant green and crisp-tender, 1 to 2 minutes. Serve immediately with lemon wedges.