Boil the pasta: Bring a large pot of salted water to a rolling boil. Cook the pasta until just al dente, usually 1 minute less than the package suggests. Reserve 1 cup of pasta water before draining.
Warm the aromatics: In a large skillet over medium heat, add a tablespoon of olive oil (or oil from the sun-dried tomato jar).
Add minced garlic and a pinch of red pepper flakes. Cook 30–60 seconds, just until fragrant.
Add the sun-dried tomatoes: Stir in the sliced sun-dried tomatoes and cook 1–2 minutes to soften and infuse the oil.
Loosen with pasta water: Pour in 1/4 cup of the reserved pasta water to create a light sauce base. Let it simmer briefly.
Toss with pasta: Add the drained pasta to the skillet and toss so everything is coated.
Turn heat to low.
Stir in the pesto: Add pesto a spoonful at a time, tossing and adding more pasta water as needed to reach a silky, glossy coating. You want the sauce to cling, not clump.
Brighten it up: Add lemon zest and a squeeze of lemon juice. Taste and adjust with salt and pepper.
Finish with cheese: Sprinkle in grated Parmesan and toss until it melts into the sauce.
Add more pasta water if it looks dry.
Optional greens and protein: Fold in a handful of spinach or arugula just until wilted. Add cooked chicken, shrimp, or chickpeas if using.
Serve: Top with extra Parmesan, torn basil, and a drizzle of olive oil. Serve hot.