If using collard greens: trim and discard tough stems, stack leaves, roll tightly and slice into 1/2-inch ribbons. Rinse thoroughly in cold water and drain well. If using spinach: rinse and roughly chop if leaves are large, drain or spin dry.

Mince aromatics

Peel and finely dice the onion. Peel and mince the garlic. If using jalapeño, halve, remove seeds for less heat and finely chop.

Cook

Heat a large skillet or sauté pan over medium heat. Add the vegetable oil and heat until shimmering.

Add the diced onion to the pan and cook, stirring occasionally, until softened and translucent, about 5–7 minutes.

Add the minced garlic and chopped jalapeño (if using) and cook, stirring constantly, for 30–45 seconds until fragrant but not browned.

Add the chopped collard greens (or spinach) in batches if necessary, stirring to wilt and combine with the aromatics. Pour in the water or vegetable broth and increase heat to bring to a gentle simmer.

Reduce heat to medium-low, cover the pan, and cook until collards are tender and fully wilted, 12–18 minutes for collards (6–8 minutes for spinach). Stir occasionally and add an extra splash of water if the pan becomes dry.

Once greens are tender, uncover and season with salt, black pepper, and red pepper flakes (if using). Stir well and simmer uncovered for 1–2 minutes to let flavors meld.

Finish by stirring in the lemon juice or vinegar, then taste and adjust seasoning. If desired, swirl in olive oil or butter for gloss and richness and sprinkle toasted sesame seeds or crushed peanuts on top.

Serve

Transfer to a serving bowl and serve hot as a side dish. Gomen pairs well with injera, rice, or as part of a vegetarian plate.

Leftovers: cool to room temperature, refrigerate in an airtight container for up to 4 days. Reheat gently on the stove with a splash of water or broth.