Add the couscous to 250ml boiling salted water and stir in. Set aside and stand for 5-10 minutes.
Fluff up the couscous with a fork and fold in the melted butter.
Alternatively, place the couscous in a bowl, then pour over the boiling salted water and leave to stand.
Preheat the oven to 180°C (160°C fan, gas 4). Wash the tomatoes, cut off a lid and remove the core with a teaspoon.
Mix 3-4 tbsp of the tomato pulp with the crumbled feta cheese, chopped parsley and couscous.
Fill the hollowed tomatoes with the couscous mixture and place the tomato lids on top. Place in an oiled baking tin and bake in the oven for 15-20 minutes.