This creamy pesto pasta has been a weeknight anchor in my home for years. I first put this simple combo together on a rainy Tuesday when I had a jar of pesto, some milk, and a stubborn pound of pasta waiting for rescue. The way the bright, herbaceous pesto softened into a warm, velvety white sauce surprised me — it felt like a restaurant dish built from pantry staples. The texture is rich yet light when you use just enough milk and a splash of reserved pasta water; the flavor balances butter and dairy with the herbal lift of basil and the nuttiness of pine nuts in many pestos.

I return to this mix because it’s forgiving: it recovers from minor mistakes like a sauce that’s slightly too thick or pasta cooked a minute past al dente. Family members lean over their bowls and always ask what I did differently that night. It’s also a great blank canvas for turning store-cupboard ingredients into a complete meal — toss in cooked chicken or shrimp, wilted spinach, or sun-dried tomatoes to make it special. The recipe below walks through a foolproof white sauce base and the small adjustments that keep the texture silky every time.

Ingredients

• Unsalted butter: 1/4 cup — I use standard unsalted butter so I can control the final seasoning. Salted works in a pinch, but reduce added salt if you choose salted butter.
• All-purpose flour: 1/4 cup — this forms the roux that thickens the milk into a silky sauce. For gluten-free, use a 1:1 gluten-free flour blend and whisk vigorously to avoid lumps.
• Whole milk: 2 cups — whole milk gives the creamiest mouthfeel; you can use 2% for a slightly lighter sauce but the texture will be less indulgent.
• Salt: 1/2 to 1 teaspoon — season to taste; start low because pesto and any added cheese can add saltiness.
• Basil pesto: 1/2 to 3/4 cup — adjust to your taste. Use a bright, verdant pesto for the best herbal lift; jarred or homemade both work well.
• Pasta: 3/4 pound (12 oz) — short shapes like penne, fusilli, or farfalle hold the sauce nicely; spaghetti or linguine also work for a classic feel.
• Optional: reserved pasta water or additional milk to thin the sauce as needed once pesto is added.

Instructions

Bring the pasta water to a boil: Fill a large pot with water, season with a generous pinch of salt, and bring to a rolling boil. Cook the pasta according to the package directions for al dente — usually 8–12 minutes depending on shape. Reserve about 1/2 to 1 cup of the cooking water before draining; this starchy liquid is your secret weapon for loosening the sauce later if needed. Make the roux-based white sauce: While the pasta cooks, melt 1/4 cup butter in a medium saucepan over medium heat. Add 1/4 cup flour and whisk constantly for about 1–2 minutes to cook out the raw flour flavor; the mixture will form a smooth paste and begin to smell slightly nutty. Keep the heat moderate so the roux does not brown — you want a blond roux for a light sauce. Whisk in milk and thicken: Slowly pour in 2 cups of milk while whisking continuously to avoid lumps. Increase heat to medium-high and continue stirring until the mixture thickens and coats the back of a spoon, about 4–6 minutes. If the sauce seems grainy, whisk vigorously or use a small immersion blender for a few seconds to fully smooth the texture. Add pesto and season: Remove the pan from the heat and stir in 1/2 to 3/4 cup pesto, tasting as you go. Add 1/2 teaspoon salt initially, then adjust to taste. The pesto will thin the sauce slightly and introduce herb, garlic, and nutty flavors; if the resulting texture is too thick for your preference, whisk in a tablespoon or two of reserved pasta water or milk until silky. Combine pasta and sauce: Drain the pasta and return it to the warm pot. Pour the pesto-white sauce over the pasta and toss gently but thoroughly so each piece is coated. If you’re adding cooked protein, wilted greens, or sun-dried tomatoes, fold them in now and warm gently for 1–2 minutes to integrate everything. Finish and serve: Serve immediately with an optional grating of Parmesan, a crack of black pepper, and a drizzle of extra virgin olive oil if desired. The sauce will cling to the pasta and set slightly as it cools, so serve while warm for the best mouthfeel.

Storage Tips

Cool leftovers to room temperature and store in an airtight container in the refrigerator for up to 3–4 days. When reheating, add a splash of milk or a tablespoon of reserved pasta water to loosen the sauce and reheat over low heat on the stove, stirring constantly until warmed through. Microwave reheating works but do it in short bursts, stirring in between to prevent hotspots and curdling. Avoid freezing the combined dish because the dairy can separate; if you plan to freeze, portion the cooked pasta and sauce separately.

Ingredient Substitutions

If you need a gluten-free version, swap the all-purpose flour for a 1:1 gluten-free flour blend (avoid straight rice flour). Use certified gluten-free pasta to keep the dish safe for those with celiac disease. For dairy-free adaptations, replace butter with olive oil and use unsweetened oat milk or a creamy plant milk; choose a dairy-free pesto or make one with sunflower seeds instead of pine nuts. For lower fat, use 2% milk and reduce butter to 2 tablespoons, though richness will be reduced.

Serving Suggestions

Pair the pasta with a simple green salad dressed in lemon vinaigrette to cut the richness. For a heartier meal, serve with roasted cherry tomatoes, garlic-roasted shrimp, or thinly sliced grilled chicken. Garnish with freshly grated Parmesan, toasted pine nuts, or a sprinkle of red pepper flakes for heat. A lemon wedge on the side brightens the herb-forward pesto and provides a fresh counterpoint to the creamy sauce.

Cultural Background

This preparation blends classic Italian techniques with American weeknight practicality. The white sauce is essentially a basic béchamel shortened for speed; the pesto is a traditional Ligurian sauce made from basil, pine nuts, garlic, olive oil, and cheese. Combining béchamel with pesto is a modern twist that balances the sauce’s body with the pesto’s aromatic intensity — a meeting of comforting creaminess and bright, herbal flavors that suits contemporary home cooking.

Seasonal Adaptations

In summer, fold in fresh cherry tomatoes and a handful of fresh basil, and use homemade pesto if basil is abundant. In fall, swap in roasted butternut squash cubes and a sage-forward pesto for a comforting seasonal shift. During winter, stir in some sautéed mushrooms and finish with a grating of aged Parmesan for a cozy, umami-rich plate.

Meal Prep Tips

Cook the pasta and sauce separately if preparing ahead: store sauce in a sealed container and heat gently with a splash of milk before tossing with freshly cooked pasta for best texture. Portion into individual containers and add a small plastic cup with a teaspoon of olive oil to protect against sticking. Reheat on the stovetop rather than the microwave to preserve creaminess.

At the table, a final flourish of extra virgin olive oil and freshly ground pepper always elevates the bowl. This pasta has seen me through hurried evenings and relaxed suppers alike — use it as a formula and make it your own.

Enjoy — and don’t be afraid to experiment. A simple swap or an added handful of greens can make this dish feel brand new each time.