Crusty pasta & broccoli bake

Name: Crusty pasta & broccoli bake
Cook time: 20 min
Total time: 20 min
Cuisine: British, European
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