For the pesto: In a food processor, puree the nuts, garlic and 2 tablespoons olive oil until smooth. Next, add the basil and mint and pulse until the leaves are minced. Add the cheese and pulse 4 to 5 times. Finally, drizzle in the remaining 2 tablespoons olive oil to finish.
For the pasta: In saute pan over high heat, add the grapeseed oil and allow to come to the verge of smoking. Next, add the shrimp and reduce the heat to medium. Continue to cook the shrimp until medium doneness, about 2 minutes, stirring throughout the time. After the shrimp are medium, add the onions and allow to cook until translucent, another 2 minutes. Add 1/4 cup pesto, stir, and then deglaze the pan with the white wine. Add the heavy cream and allow to reduce by half the volume, 2 to 3 minutes. Finally, add the pasta and stir. Finish seasoning with salt, pepper and additional wine if necessary. Allow to warm for 2 minutes, and then portion and serve. Top with the parsley and tomatoes.