Crusty pasta & broccoli bake

INGREDIENTS

• 400g penne or macaroni
• 1 red onion , roughly chopped
• 250g head broccoli , stalks chopped and florets halved
• 1 vegetable stock cube
• 1 tsp French or German mustard
• 200g pot half fat crème fraîche
• 100g grated mature Gruyère or cheddar
• small handful parsley leaves, chopped
• 4 tbsp fresh white breadcrumbs (or put 1 slice crustless white bread through a food processor)
• ½ tsp dried mixed herbs or thyme