I made this exactly as written using homemade stock and yukon gold potatoes. It was good but I agree with a previous reviewer and think it would be enhanced with the addition of some tasty cheese. The instructions don't mention when to add the rosemary and thyme so I sprinkled some on top of the casserole before baking (almost forgot to add it or I would probably have added it to the stock).
We used Yukon gold potatoes and Vadalia onions. I opted to use warm milk along with the vegetable stock, plus I added some parmesan cheese to the top layer. It was good but I think the next time I make it I'll add some extra sharp cheddar cheese between the layers. Made for VIP Veg 'N Swap #18 tag.
This was very tasty and helped me to use up the potatoes I bought at the market. I added some butter to the inner layers too. I also used shallots instead of onions. However, the taste wasn't really amazing. It tastes rather like an English recipe for potatoes I made once--it fills you up but doesn't amaze. Am living in France so I think I'll go eat potatoes that someone else makes ;)
We really enjoyed this gratin. It was simple (with a mandolin)and had a nice clean taste. I baked this at 350F and served it with grilled lamb chops for a delicious meal. Thanks FT.