This dish is only as good as the vegetables you buy, so use that as your starting point and you'll be on to an absolute winner! Here are some tips on buying and preparing a selection of veg...
In most supermarkets these days you can get fresh baby carrots with their green tops. Leave about an inch of the tops on and just give the carrots a scrub.
Do the same with some lovely radishes. You can get some marbled pink and white oval ones now, which are crunchy and peppery. Again, leave the tops on as these make good handles when it comes to dipping.
Use nice crunchy lettuces. Sweeter lettuces like cos and Romaine are good for dipping – I try to use the inner part, keeping the outer leaves for another salad. I leave the stalk on and then cut the lettuce into quarters, and that way they stay in one piece, but you don't have to do this. The important thing is to get good chunks of vegetables. I like to contrast the sweet lettuces with slightly more bitter ones like radicchio or endive.
If you've got some young asparagus that's just come into season, it's really nice eaten raw. Feel free to use your imagination on the veggie side. Little fingers of celery or celeriac are also good. However, you often come across people who use raw cauliflower with dips – I personally would prefer colonic irrigation! I think cauliflower and broccoli are just awful eaten raw, so I wouldn't suggest using them here.
Whiz the yoghurt and mint up in a food processor for half a minute or so. Add the peas and the Parmesan and whiz again – the peas will break down and the yoghurt will become green. Put into a bowl, correcting the seasoning with extra salt and pepper and a good squeeze of lemon juice. When you add the lemon juice and peas to the yoghurt, quite often it splits and turns into a kind of cheese, but this is absolutely fine. It depends on the type of yoghurt you use and how acidic your lemon is. Just pour away any excess water. Usually, though, it doesn't split and is more like a purée, but both ways are good.
The best way to serve this is to put the dip into a bowl and have a big board next to it with your veggies on. And have some salt and pepper to hand in case you need it. It's a good sociable way to start a meal.
• adapted from Jamie's Dinners