Prepare the Garlic Breadcrumbs: Heat 3 tablespoons of olive oil in a skillet over medium-high heat. Add the mashed garlic and cook for 1-2 minutes until fragrant. Stir in the panko breadcrumbs, kosher salt, and black pepper, and toast for 4-5 minutes, stirring frequently, until golden brown. Set aside to cool.

Cook the Pasta: Bring a large pot of salted water to a boil. Cook the penne pasta according to package instructions until al dente. Reserve ¼ cup of the starchy pasta water, then drain and set the pasta aside.

Make the Walnut Pesto: In a food processor, combine parsley, basil, garlic, walnuts, Parmesan cheese, kosher salt, and black pepper. Pulse until crumbly. Slowly drizzle in ⅓ cup olive oil while pulsing until the pesto forms a creamy texture. Taste and adjust seasoning as needed.

Toss the Pasta: In a large bowl or the pasta pot, combine the warm pasta with the walnut pesto. Add a splash of the reserved pasta water to create a silky-smooth sauce that coats every bite.

Assemble and Serve: Plate the pasta and generously sprinkle the toasted garlic breadcrumbs on top. Serve immediately and enjoy!