I made those fantastic eggs in baked potatoes for brunch but they left me with a lot of roasted potatoes. 
Not the worst situation that I’ve ever been in and easily fixed since the organic bin this week had gorgeous leeks in it.  I sliced up two large ones.
Sweated them in a pan with a tablespoon of butter until they began to soften.
Added my lovely potatoes (this was the flesh from 12 small to medium potatoes, you can always use 6 large potatoes and just make this recipe by peeling and cubing whole potatoes.  Increase your cooking time to allow the cubes to cook and then continue the recipe from there).
Add enough chicken stock to cover the vegetables.  If you’d like this to be vegan, just use oil to sweat the leeks and substitute vegetable stock.
Blitz with a handblender or put in a blender or use your food processor or use a potato masher (you’ll just have a chunkier soup).
Now to season; pepper, salt and my secret weapon, a heaping teaspoon of horseradish.  Weird but it really adds to the dish.