Warm a large skillet over medium heat and add the butter, allowing it to melt and foam gently, filling the kitchen with a nutty aroma.
Add the thinly sliced garlic to the skillet and cook, stirring constantly, until fragrant and just golden, about 30 seconds to 1 minute. You'll notice a beautiful aroma and the garlic will turn a light, toasted color.
Toss in the peas, stirring well to coat them evenly in the garlic butter. Cook for about 2-3 minutes, until the peas are bright green and tender, with a slight pop when pressed.
Season with salt and freshly ground black pepper to taste. If using, sprinkle chili flakes for a touch of heat, and stir to combine.
Finish by adding lemon zest for a bright, citrusy note. Gently toss everything together and cook for another 30 seconds to meld flavors.
Remove the skillet from heat and transfer the peas to a serving dish. Serve immediately, enjoying the tender peas coated in fragrant garlic butter with a hint of citrus and spice.