Kevin, our gardener and good friend caught an extra trout on his fishing trip the other day so he gifted us a nice one. It's the largest trout I've ever seen, it could easily have fed 4 people. It was cleaned and head off so I just stuffed diced onion with salt, pepper and dill in the cavity, drizzled a little olive oil over top of it and put it in the oven at 325F for about an hour.
Mashed potatoes were standard. Peel, chop, boil, drain, mash, butter, salt and a little milk. The only thing to say about mashed potatoes is don't over process them, it turns them into a thick paste no one will be able to eat.
Asparagus, you eat the end with the proto flowers. Hold the cut end in your fingers and bend the stalk over. It will snap at the right place. Below the snap to the cut end is fibrous, use for stock only. I have an asparagus cooker which is a tall narrow pot with mesh insert. The asparagus stand up and steam in it. Works great. Any steamer will work or just boil them lightly in a little water.
1 egg yolk
1/3 cup butter
1/2 lemon juiced
1 tsp water
Melt the butter but don't get it hot. Slowly whisk the butter into the egg yolk as for mayonnaise. When all the butter is taken up the sauce should be thick. If it's runny, butter went in too fast and broke the sauce. Fix it by getting another yolk and slowly adding the broken sauce to the fresh yolk. Go slow, don't break it again.
Add lemon, water and salt. Bring to a simmer on medium low heat or over a double boiler. Whisk continuously. If it's too thick add 1/2 tsp water. Pour over fish and asparagus. Garnish with a little chopped parsley.
It was every bit as good as it looked!