Mrs Clark’s recipe is so adaptable that it doesn’t have to be veggie at all and it doesn’t have to be topped with mashed potatoes either. You could alternatively put the mixture into a short rust pastry (that works well) and instead of vegetables you could use fish in the sauce with the potato topping. Ingenious!
1 stick of celery
2 medium carrots
1 small onion
Trimmed green beans
Dice and saute in butter and a little oil until soft meanwhile make up a hollandaise sauce ( packet mix is fine)
Add vegetables to the sauce and transfer to an oven proof dish top with mashed potato and cheese and oven Cook until potato and cheese are nicely browned.