The following are from my Welsh collection and do have bacon added for fuller flavour but there is no reason to include this for true vegetarians.

 
Tatws Stem

Place thickly sliced potato in a large saucepan and cover with a layer of sliced onion. Continue to arrange alternate layers finishing with potatos. Sprinkle the top with a little flour and then rashers of bacon. Fill with water and place a piece of greased paper over the bacon. Place a plate on top and with the lid on simmer gently until cooked.

 
Stwnsh

Cook diced swede and potato plus seasoning and when soft mash together. An accompaniment to crisply cooked bacon.