Bring a large pot of salted water to the boil and cook the orzo following pack instructions until al dente. Drain, then immediately plunge into cold water to halt the cooking.
Halve the lemon, then cut the tips from the artichokes with a serrated knife and strip away the tough outer leaves. Pare away any tough bits from the bases, and trim the stalks to about 5cm, peeling away the outer skins to reveal the white cores. Quarter the artichokes, scooping out the hairy chokes, then halve each quarter. Transfer to a bowl and squeeze over the juice from half the lemon, tossing to coat.
Heat the oil in a heavy-bottomed frying pan over a medium heat and fry the potatoes, spring onions, garlic and artichokes, stirring for 5-6 mins until the potatoes are starting to brown. Add the mint sprig, wine and 500ml water, then season, cover and simmer for 12-15 mins until the potatoes and artichokes are tender. Add the broad beans and peas and cook for 2 mins more until tender but still retaining their bright colour. Remove the pan from the heat. Drain the orzo and stir into the pan with the chopped mint and most of the lemon zest, then leave to stand for a couple of minutes so the orzo can absorb the flavours. Taste for seasoning and adjust the salt, and squeeze over the remaining lemon half, if you think it needs it.
Dish into warmed bowls and top with spoonfuls of the ricotta. Scatter over the crushed pink peppercorns and the remaining lemon zest, then grate over some pecorino to serve.