Halve the potatoes or cut them into bite-sized pieces, and toss them with a couple of tablespoons of oil, salt and freshly ground pepper.If you like, sprinkle them with a little dried herb too - oregano, thyme or similar.
Roast the potatoes in the oven at 200°C for about 30 minutes, or in an air fryer at 180°C for about 30 minutes - or until golden.Then leave them to cool slightly.
Put the feta in a mini chopper together with a couple of tablespoons of the yogurt, the garlic, lemon zest and juice. Blend until you have a smooth, even cream - add a couple more tablespoons of yogurt if needed.
Season with freshly ground pepper and a pinch of salt, and add the rest of the yogurt. Blend briefly - not for too long, or the whipped feta can turn thin.You can also stir the last of the yogurt in by hand instead.
Spread the whipped feta on a plate and top with the roasted potatoes, parsley, a drizzle of olive oil and freshly ground pepper.Serve straight away.