To make the pesto, crush the garlic to a paste with a pinch of salt using a pestle and mortar. Add the pine nuts and pound to a coarse paste, then tear in the basil and mint, pounding again until they’ve broken down. Stir in the oil and cheese, then taste for seasoning – add more cheese if you like.
Heat the oil and butter in a large non-stick frying pan over a medium heat. Add the courgettes, sprinkle in the chilli flakes and nutmeg, and season with salt and pepper. Fry for 3-5 mins until the courgettes are golden and softened. Add the spring onions and lemon zest, and stir for a minute or two. Tip in the rice and stir to coat in the oil until translucent, about 2 mins.
Pour in the wine, then cook for a couple of minutes until it’s mostly evaporated. Add a ladleful of the stock and stir for a few minutes until it’s absorbed. Continue adding a ladleful at a time for 20-30 mins, stirring continually, until all of the stock is absorbed.
Stir in the blanched broad beans and flowers, if using, and warm through for 2 mins. Remove from the heat and stir through the parmesan. Allow to sit for about 5 mins, then swirl through half of the pesto. Any remaining pesto will keep chilled for up to two days.
Divide the risotto between bowls and scatter with the extra basil leaves, extra cheese and another spoonful of the pesto, if you like.