Heat a portion of the oil in a Dutch oven over high heat until it shimmers. Add the spinach one handful at a time, tossing each batch until it wilts enough to make room for more. Cook until all the leaves are just wilted, about 1 minute—they should still be bright green.

Transfer the spinach to a colander and use your tongs to squeeze out as much liquid as possible; this prevents the final dish from becoming soggy.

Wipe the pot dry with paper towels, then add the garlic and the remaining oil over medium heat. Cook until the garlic is fragrant and just starting to turn golden.

Return the squeezed spinach to the pot and toss it thoroughly to coat with the garlic oil.

Remove the pot from the heat and season with salt and lemon juice. Serve immediately while hot and vibrant.