How to Make It
In a small saucepan, stir together the olive oil, garlic, chiles and 1 teaspoon of salt. Stir in the lemon zest. Bring the oil to a gentle simmer over low heat and cook until the garlic begins to brown slightly, about 15 minutes. Remove from the heat and let the oil infuse for 1 hour. Discard the chiles and lemon zest and reserve the garlic.
Meanwhile, in a large pot of salted boiling water, cook the spinach until bright green, 15 seconds. Using tongs, transfer the spinach to a bowl of ice water and let cool for 10 seconds. Drain the spinach in a colander, pressing down to remove all the water. Pat dry with paper towels.
Heat a large skillet. Add the spinach and cook over moderately high heat until beginning to sizzle. Add the garlic oil and toss until the spinach is hot, about 2 minutes. Transfer the spinach and reserved garlic to a colander set over a bowl to drain. Mound the spinach on a platter, season with salt and pepper and serve.