What I had for dinner:
This is a variation on a theme similar to what I posted a while ago. Mussels in the shell are messy to eat, so the idea is to make something that can all be eaten with the fingers. Since fries are finger food par excellence, there was no reason to search any further for a vegetable, though asparagus could be an alternative.
The potatoes were cut, washed, and thoroughly dried, then coated with olive oil in a plastic bag, patted dry, and drenched in freshly ground black pepper. They were then baked at 400-450F for about 15 min (it depends on the thickness) until golden.
Four large shiitake were diced and cooked in a small saucepan until all the liquid evaporated. A large handful of chopped fleshy red peppers (moderately hot "cherry", "tomato" or the like), an inch of ginger (peeled but not cut), one whole bruised clove of garlic, and a couple of tablespoons of crushed tomatoes were added all at once, and cooked for a few minutes.
In a large pot with a good lid, 1/4 cup of beer was brought to a boil, and mussels were added. The pot was closed and left to boil for 2 minutes, then the sauce was added, mixed in, and left to cook for another 3 minutes with the lid ajar. For more varity, one can also add at the last moment some sauteed shrimps or scallops.
Serve in a deep bowl, with the potatoes on top, and eat with the hands, using mussel shells to scoop sauce from the bottom of the bowl. Provide plenty of paper towels!