Use baby spinach if possible — no trimming needed. For mature spinach, pinch off thick woody stems. Rinse under cold water, then spin or pat dry. A little surface moisture is fine and helps the leaves steam, but shake off excess to avoid splattering in hot oil. Measure out your oil, garlic, and salt before turning on the heat — things move fast once spinach hits the pan.

Heat a large skillet over medium heat. Add enough olive oil to lightly coat the bottom and let it heat about 30 seconds until shimmering. If using garlic, add it now and stir 30 seconds until fragrant, do not let it brown. Add spinach to the pan. It will look like too much — that is fine. Pack in as much as fits, cover with a lid, and let steam help it collapse. Cook covered 1 to 2 minutes for baby spinach, up to 3 minutes for larger leaves. Remove the lid and toss with tongs, pulling wilted leaves from the bottom up. Continue tossing every 30 seconds if the pan is full. Total cook time is 1 to 5 minutes depending on spinach type and pan fullness. Pull off the heat as soon as the leaves are just wilted and a deep, vibrant green. Spinach turns watery fast, so watch closely.

Pull the pan the moment the last leaves collapse and the color turns deep, bright green. No resting needed — serve immediately. Season with a pinch of kosher salt before or after cooking. A squeeze of lemon juice or a drizzle of olive oil at the end lifts the flavor. Do not overcook; excess heat makes spinach soggy and dull. Use the largest skillet you have to avoid crowding, and cover it at the start to help the leaves wilt evenly.