Bring a small pot of water to the boil and add the peas. Simmer gently for 2 to 3 minutes until just tender and then drain. Place the peas in a bowl of cold water and set aside.
Melt a small knob of butter together with a teaspoon of extra-virgin olive oil in a frying pan over medium heat. When the butter has melted, add the asparagus and sauté for a few minutes until softened and just starting to colour.
Add the peas and broad beans and cook for another minute. Sprinkle with a pinch of sea salt to season before removing the pan from the heat.
Place the cooked quinoa in a large bowl and dress it with a tablespoon of olive oil and the juice of half a lemon.
Add the finely sliced mint leaves and the crumbled feta and stir through. Season with sea salt and black pepper to taste.
Pile the quinoa in the centre of a large serving platter and sprinkle the rocket leaves around the edges (if using).
Scatter the cooked vegetables over the quinoa and garnish with additional mint if desired.
To make the yoghurt dressing, place all of the ingredients in a small bowl and whisk to combine.
Drizzle the yoghurt dressing over the salad, or serve in individual portions on the side.