In a large pot of salted boiling water, cook the penne according to package instructions until al dente. Drain and set aside, reserving 1/2 cup of pasta water.
In a food processor, combine basil leaves, pine nuts, Parmesan cheese, and minced garlic. Pulse until well blended. While the processor is running, gradually add olive oil until the mixture is smooth. Season with salt and pepper to taste.
In a large skillet over medium heat, add a bit of olive oil. Once hot, add the shrimp in a single layer. Cook for 2-3 minutes on one side until they turn pink and opaque. Flip and cook for another 1-2 minutes. Remove the shrimp from the skillet and set aside.
In the same skillet, add the cooked penne and pesto. Toss until the pasta is well coated. If the mixture seems too thick, add reserved pasta water a little at a time to achieve desired consistency.
Gently fold in the cooked shrimp to the pasta and pesto mixture until evenly distributed and heated through.
Divide the pasta among plates. Garnish with halved cherry tomatoes and extra basil leaves before serving.