Prepare the Pesto: In a food processor, combine fresh basil leaves, toasted pine nuts, garlic cloves, and Parmesan cheese. Pulse until coarsely chopped, then slowly drizzle in olive oil until smooth. Finish with lemon juice, salt, and pepper. Set aside.

Cook the Pasta: Bring a large pot of salted water to a boil, add pasta, and cook according to package instructions (8-10 minutes) until al dente. Reserve a cup of pasta water, drain, and toss with pesto.

Marinate the Shrimp: In a bowl, mix olive oil, minced garlic, lemon zest, salt, and optional red pepper flakes. Add shrimp and marinate for 15 minutes.

Grill the Shrimp: Preheat grill to medium-high. Skewer shrimp or place them on the grill. Cook for 2-3 minutes on each side until opaque.

Assemble the Stack: Layer pesto-coated pasta on a plate, followed by grilled shrimp on top, creating height and visual appeal.

Garnish and Serve: Drizzle remaining pesto over the stack, sprinkle with toasted pine nuts and herbs, and serve immediately.