Start by boiling a pot of water and add your penne pasta. You will know it is ready when it starts to soften and the water is bubbling vigorously. Keep an eye on it to avoid overcooking, as you want it al dente for that nice bite in the finished dish.
Melt the butter in a large skillet over medium heat. Toss in the minced garlic and let it cook until fragrant, about 1 minute. Garlic can burn quickly, so stir it often and keep your senses tuned to that delicious aroma to know it is done.
Pour in the whole milk and add the cream cheese to the skillet, stirring until it melts and combines smoothly. You will see the sauce start to thicken, creating a luscious texture. Be careful not to let it boil, as that can make the sauce separate.
Add the grated Parmesan to the creamy mixture and stir until melted and well blended. You will get a beautiful cheesy sauce that coats everything evenly. Just a heads up: using pre-grated cheese can lead to a grainy texture, so fresh is best if you can swing it.
Sprinkle in the salt and freshly cracked black pepper, tasting as you go to find that ideal flavor. You will want a nice peppery bite to contrast the creaminess. Just remember, a little seasoning goes a long way, so avoid overdoing it.
Toss the baby spinach into the skillet, stirring it until it wilts down and combines perfectly with the sauce. You will see it shrink and turn a vibrant green, which is a beautiful sign it is ready. Keep an eye out—too long, and it will lose its fresh texture.
Drain the penne and add it to the skillet with the sauce, giving everything a good toss to coat the pasta evenly. You should see that creamy goodness clinging to each piece. If it feels too thick, a splash of pasta water can help lighten it up.
Dish out your Spinach Alfredo Pasta onto plates and enjoy the creamy, cheesy flavors. The delightful visual of the vibrant greens against the white sauce will have everyone ready to dig in. Just be cautious with leftovers; refrigerate quickly to keep everything fresh.