Quick, vibrant, and full of fresh flavor, Pesto Spaghetti is a simple pasta dinner that brings together kale, basil, walnuts, and Pecorino Romano in one glossy, savory bowl. It is reliable for busy nights, rich without feeling heavy, and easy to finish with pantry-friendly ingredients.
Some pasta dinners are all about comfort, while others lean bright and fresh. This one gives you both. The spaghetti stays familiar and satisfying, but the homemade pesto adds a greener, livelier flavor that makes the whole dish feel a little more special.
The mix of kale and basil works beautifully here. Basil gives the sauce its classic fragrant lift, while kale adds body and depth, so the pesto clings to the noodles instead of sliding off. A little Pecorino Romano brings saltiness, and walnuts round everything out with a toasty, buttery note.
This is the kind of meal that fits real life. You can make it on a weeknight, serve it for a casual dinner with friends, or keep it in your back pocket for those evenings when you want something homemade that still feels low effort. Once you learn the balance of pesto and pasta water, it is the sort of dish you will come back to often.
Pesto Spaghetti Ingredients
- Spaghetti gives you the classic long noodle shape that catches the pesto well and keeps the dish hearty enough for a main course.
- Kale leaves add earthiness, color, and a little extra body to the sauce, helping create a pesto that feels substantial and balanced.
- Fresh basil brings the bright, aromatic flavor that makes pesto so appealing and keeps the finished pasta tasting fresh.
- Extra virgin olive oil smooths out the pesto and helps turn the greens, nuts, and cheese into a silky sauce.
- Pecorino Romano adds sharp, salty richness and gives the pesto a savory backbone that stands up well to the kale.
- Walnuts lend texture and mellow nuttiness. They also make the pesto feel richer without needing extra ingredients.
- Garlic adds a punchy, savory note that wakes up the whole sauce.
- Salt and black pepper season both the pasta and the pesto so the flavors taste clear instead of flat.
- A small pinch of sugar softens the natural bitterness of the kale and helps the basil and cheese taste rounder.
- Extra chopped walnuts and grated Pecorino Romano finish the dish with crunch, contrast, and a final layer of flavor.
How to Make This Pesto Spaghetti
STEP 1: Bring a large pot of water to a boil and salt it well. Cook the spaghetti until al dente, stirring now and then so the strands stay separate and cook evenly.
STEP 2: While the pasta cooks, add the kale and basil to a food processor and pulse until finely chopped. Breaking down the greens first helps the pesto blend more evenly once the oil and cheese go in.
STEP 3: Add the olive oil, Pecorino Romano, walnuts, garlic, salt, black pepper, and sugar. Pulse until the mixture turns into a vivid green pesto with a smooth, spoonable texture. It should look thick but still soft enough to toss with hot pasta.
STEP 4: Before draining the spaghetti, scoop out some of the pasta water. This step matters more than it seems because that starchy water helps the pesto loosen into a light sauce instead of staying dense.
STEP 5: Return the drained spaghetti to the pot and add the pesto with part of the reserved pasta water. Toss well so the noodles are evenly coated. Add a little more water as needed until the sauce looks glossy and lightly clings to each strand.
STEP 6: Taste the pasta before serving. Depending on your cheese and how salty your pasta water was, you may want a touch more salt or pepper. This quick check makes the final bowl taste more polished.
STEP 7: If you want extra depth, toast the garnish walnuts in the oven until fragrant and lightly colored. Let them cool before sprinkling them over the pasta so they stay crisp.
STEP 8: Serve the spaghetti warm with more grated Pecorino Romano and chopped walnuts on top. That final finish gives the dish a great mix of creamy, nutty, and savory textures in every bite.
Helpful Tips
- Use the pasta water gradually rather than all at once. You want the pesto to loosen just enough to coat the spaghetti without becoming watery.
- Do not overprocess the pesto for too long after adding the oil. A few pulses are enough to keep the flavor fresh and the texture pleasantly thick.
- Toast the walnuts for garnish if you have the extra few minutes. It is optional, but it gives the finished dish a deeper flavor and a better crunch.
Can I make this ahead of time?
Yes, but it is best when freshly tossed. You can make the pesto ahead and refrigerate it, then cook the spaghetti right before serving. That way the noodles stay springy and the sauce keeps its brightest flavor.
Can I use only basil or only kale?
You can, but the balance changes. All basil will taste more classic and herb-forward, while all kale will be earthier and slightly stronger. Using both gives you a fuller pesto that still tastes fresh and familiar.
Why is my pesto spaghetti too thick?
That usually means it needs more reserved pasta water. Pesto can tighten up quickly once it hits hot noodles. Adding small splashes of starchy water while tossing helps turn it into a smooth sauce instead of a heavy paste.
Do I have to toast the walnuts?
No, the dish still works without that step. Toasting simply deepens the walnut flavor and gives the garnish a more noticeable crunch. When you have the time, it is a small touch that makes the bowl feel more finished.
Perfect Pairings
A crisp green salad is one of the easiest sides to serve here. Something with a lemony dressing works especially well because it cuts through the richness of the cheese and olive oil without competing with the pesto.
Roasted vegetables also make a great match. Think zucchini, asparagus, or cherry tomatoes, all of which fit naturally with the bright, savory profile of the pasta and turn it into a fuller dinner.
For a simple bread option, serve it with warm garlic bread or a rustic loaf. That is especially useful if you want something to catch any pesto left at the bottom of the bowl.
Keeping Leftovers Fresh
Store leftover pesto spaghetti in an airtight container in the refrigerator for up to 3 days. The pesto may thicken as it sits, which is completely normal.
To reheat, warm it gently on the stovetop or in the microwave with a small splash of water. This helps loosen the sauce so it coats the noodles again instead of drying out.
Freezing the fully dressed pasta is not ideal because the texture of the spaghetti and pesto can change too much after thawing. If you want to prep ahead, freeze the pesto separately and cook fresh pasta when you are ready to serve.
Pesto Spaghetti
Ingredients
For the Pasta
- 1 pound spaghetti such as Barilla No. 5
- 1 teaspoon salt
- Additional salt for the pasta water
For the Pesto
- 2 cups kale leaves tightly packed, stems removed
- 1 cup fresh basil leaves firmly packed
- 1/2 cup extra virgin olive oil preferably high quality
- 1/2 cup Pecorino Romano finely grated
- 1/3 cup walnuts
- 2 garlic cloves freshly minced
- 1 teaspoon salt
- 1/4 teaspoon black pepper
- 1/4 teaspoon sugar
For the Garnish
- 1/3 cup Pecorino Romano grated
- 1/2 cup walnuts chopped
Instructions
- Bring a large pot of water to a rolling boil and season it generously with extra salt. Add the spaghetti and cook until al dente, about 10 minutes or according to the package directions, stirring from time to time so the strands do not cling together.
- While the pasta is cooking, place the kale and basil into a food processor fitted with the steel blade. Process until the leaves are finely broken down.
- Add the olive oil, grated Pecorino Romano, walnuts, minced garlic, salt, black pepper, and sugar to the processor. Pulse until the mixture becomes smooth and forms a vivid green pesto.
- Before draining the spaghetti, reserve 1 cup of the cooking water. Drain the pasta, then return it to the pot.
- Add the pesto to the hot spaghetti along with 1/2 cup of the reserved pasta water. Toss thoroughly until the sauce coats the noodles evenly. Add more of the reserved water a little at a time if needed to loosen the sauce to your preferred consistency. Taste and adjust the seasoning as needed.
- For the optional garnish, preheat the oven to 350°F. Arrange the walnuts in a single layer on a baking sheet and toast them for 6 to 10 minutes, watching closely, until fragrant and lightly colored. Remove them from the oven at once and transfer to a plate to cool.
- Serve the spaghetti warm, topped with the grated Pecorino Romano and chopped walnuts.
