Heat a wide skillet over medium-high heat until shimmering, then add the olive oil, swirling to coat the bottom evenly.
Add the finely chopped garlic to the hot oil, sizzling gently until fragrant and just beginning to turn golden, about 30 seconds. Be careful not to let it burn, as this can make it bitter.
Immediately add the washed spinach to the skillet, piling it in as it seems like too much, then use your spatula or tongs to toss and coat the greens with the garlic oil.
Cook the spinach, stirring constantly, for about 1-2 minutes until it wilts completely and turns a vibrant bright green, with some edges slightly darkened and crispy.
Add a splash of lemon juice and season with a pinch of flaky sea salt and red pepper flakes, tossing everything together to distribute evenly.
Give one final toss, ensuring the garlic is crispy and fragrant, the greens are tender yet bright, and the seasoning is balanced.
Serve immediately while hot, enjoying the fragrant, tender greens with crispy garlic edges and a bright citrus finish.