Optional step: To mellow the garlic flavour, begin by adding the chopped garlic to a bowl along with the lemon juice.
Bring a pan of water to the boil. Add the broad beans, return to the boil, and simmer for a few minutes until tender. Drain, rinse under cold water to cool, and set aside.
To a food processor, add the cooled broad beans, garlic, lemon juice, olive oil, and mint leaves.
Add half of the lemon zest, season with salt and pepper, and blend until smooth, scraping down the sides if necessary with a spatula or spoon.
If the mix seems very thick, add a few tablespoons of cold water and continue to blend. Repeat until you have a consistency that's smooth, light, and fluffy.
Adjust the seasoning to taste, adding any extra lemon zest, mint, salt, and pepper.
Serve the broad bean dip as it is or top with a little extra olive oil, fresh mint leaves, and toasted pine nuts.