Place all pesto ingredients in a blender and season with pepper. Blend until mixture is a thick puree. Add 1–2 tablespoons of water to loosen and pulse for a few seconds. Put pesto into a bowl, cover and refrigerate.
Heat 1 tablespoon of olive oil in a frying pan over a medium heat. Add garlic and cook for a few minutes until golden in colour. Add zucchini and chilli flakes and cook for 1 minute, stirring gently.
Add cannellini beans and vegetable stock and simmer for 5 minutes until warm. Mash one-quarter of the cooked beans roughly into the broth to thicken. Remove from heat and season to taste with pepper and salt.
Heat the remaining 1 tablespoon oil in separate frying pan over medium heat. Season shrimp and add to frying pan, cooking for 2–3 minutes until they have changed colour and are cooked through.
Remove pesto from fridge and fold into bean mixture. Spoon onto plates and top with shrimp, lemon zest, parsley, extra oil and chilli flakes.