Prep the spinach: Rinse the spinach and shake off any excess water. No need to fully dry - some moisture helps it wilt.
Heat the pan: In a large sauté pan or skillet, heat olive oil over medium heat.
Sauté the garlic: Add the sliced or minced garlic, cooking for about 30 seconds until fragrant. Do not brown the garlic - it will turn bitter.
Add the spinach: Add the spinach in large handfuls. It will look like a lot, but it cooks down significantly. Toss gently with tongs as it begins to wilt.
Season: Once wilted (about 2–3 minutes), add: Salt, Fresh black pepper; Add the optional butter here for a glossy finish.
Finish and serve: Remove from heat immediately. Squeeze a light touch of lemon over the top to brighten the flavors (optional). Serve warm alongside scallops, fish, or grilled meats.