Preheat the oven to 220 C, Fan 200 C, Gas 7. Place the feta on a baking tray lined with baking paper. Grate over the zest of half the lemon, sprinkle over the bashed coriander seeds and season with some black pepper. Drizzle with a little oil then roast in the oven for 25 minutes until the feta is starting to turn nicely golden.