Put the feta, yogurt, lemon zest, herbs and oil in a food processor or high-speed blender and pulse until the mixture is a creamy, smooth texture. Spoon into a shallow serving bowl and set aside.

For the topping, gently toast the coriander seeds in a dry frying pan over a low- medium heat for a few minutes until fragrant. Scatter the seeds over the dip, along with the za’atar or chilli flakes. Drizzle over a little olive oil and serve with the radishes for dunking.