Tip the antipasti and its oil into a roasting tin, squeeze over the lemon juice, reserving the zest, and place the feta in the middle of the tin. Season with black pepper and drizzle over a little extra olive oil. Bake in the oven at 180C/160C fan/gas 4 for 25 mins. Toast the pittas for 1-2 minutes until warmed through. Scatter the lemon zest over the feta. Serve with the pittas.