Bring a large pot of water to a boil and season it generously with salt. Cook the pasta according to package directions until al dente. Before draining, reserve at least one full cup of the pasta cooking water and set it aside. Then drain the pasta.
While the pasta cooks, prepare the pesto by adding the basil leaves, half the garlic, Parmesan cheese, olive oil, and half of the salt to a blender or food processor. Blend until smooth and cohesive, stopping to scrape down the sides if needed.
Taste the pesto and add more salt if needed. The pesto should taste slightly more seasoned than you expect, as it will be diluted when combined with pasta.
Heat two tablespoons of olive oil in a wide skillet over medium heat. Place the halved tomatoes cut-side down and cook undisturbed for about 2 minutes. Stir gently, then add the remaining minced garlic and cook briefly until fragrant, without browning.
In a separate skillet, heat the remaining olive oil and add the panko breadcrumbs. Toast, stirring until golden and crisp, then remove from the heat immediately and set aside.
Add the drained pasta directly into the skillet with the tomatoes. Pour in the pesto and about one-quarter cup of the reserved pasta water. Toss continuously so the sauce loosens and begins coating the pasta. Add a little more pasta water, a little at a time, while tossing until the pasta appears glossy and evenly coated rather than dry or clumped.
Remove from heat, taste, and adjust seasoning with salt if needed. Divide into bowls and finish with toasted panko, extra Parmesan, and torn fresh basil leaves.
Notes
Season pesto properly: It should taste slightly strong before adding to pasta.
Don’t skip pasta water: It creates a smooth, cohesive sauce.
Toast panko carefully: Remove as soon as golden to avoid burning.
Cook tomatoes cut-side down first: This brings out their natural sweetness.
Toss continuously: Helps emulsify the sauce for a silky finish.