BBC Food - Recipes - Picnic basket pie

Ingredients

• 600g/1lb 5oz plain flour
• 300g/10½oz unsalted butter , at room temperature but not soft
• salt
• ½ tsp baking powder
• 50ml/2fl oz milk , to brush
• 1 free-range egg , beaten, to glaze
• 2 tbsp sunflower oil
• 2 medium red onions , chopped
• 2 garlic cloves, in whole cloves, skin on, lightly crushed under fork
• 3 Romano red peppers , chopped
• 1 large courgette , chopped
• 1 aubergine , chopped into 1cm/½in cubes
• salt and freshly ground black pepper
• 100g/3½oz couscous
• 90g/3¼oz sun-dried tomato paste
• 250g/9oz halloumi
• 100g/3½oz mozzarella , grated
• small bunch fresh oregano
• small bunch fresh basil
• 100g/3½oz caster sugar