Bring a large pot of salted water to a rolling boil, then add the pasta. Cook until just al dente, about 8 minutes, stirring occasionally and listening for a gentle bubbling.
While the pasta cooks, mince the garlic cloves and prepare your ingredients: wash and roughly chop the spinach, and keep the peas ready.
Drain the pasta in a colander, reserving about half a cup of the starchy cooking water, then set aside.
Heat the olive oil in a large skillet over medium heat until it shimmers and you can smell the fruity aroma—about 1 minute.
Add the minced garlic to the hot oil and sauté gently for about 30 seconds until fragrant and just beginning to turn golden, avoiding browning.
Toss in the fresh peas, stirring constantly, and cook for 2-3 minutes until they are tender and smell sweet, or if frozen, until heated through and slightly plump.
Add the drained pasta directly into the skillet with the peas and garlic, tossing gently to combine.
Sprinkle the chopped spinach over the pasta and stir gently for about 1-2 minutes until wilted but still bright green and slightly crisp.
Squeeze the lemon juice over the mixture, then season with a pinch of salt and freshly ground black pepper—taste and adjust as needed.
If the mixture seems dry, splash in a little of the reserved pasta water and toss to loosen the sauce, creating a light, glossy coating.
Remove the skillet from heat, then sprinkle with grated Parmesan cheese or nutritional yeast for extra umami flavor.
Serve immediately, garnished with a little extra lemon zest or cheese if desired, and enjoy the fresh, vibrant flavors in every bite.