Heat a pot of water to a boil for pasta, once boiling salt water and cook pasta to al dente.
Meanwhile, heat a large skillet with EVOO, 2 turns of the pan, over medium heat, add butter to oil and melt, add onions, garlic and cook to soften 5-6 minutes.
In a saucepot, bring chicken stock to a boil. Drop the peas into the stock and cook for 5 minutes. Remove half the peas and add to the skillet. Sprinkle with sugar, salt and pepper and let cook for another 2-3 minutes.
In a food processor, add parsley, tarragon, mint, lemon zest, remaining peas, and stock. Process until combined.
Just before draining pasta reserve a cup of starchy cooking water, in case sauce is too thick.