First we start with the potatoes. These are fresh, not frozen. You need to give them a wash then boil or microwave them until soft. Not quite ready to eat soft but soft enough so you can poke them with a fork and then smash them down. Use a dish towel and place the potato inside. Now use the palm of your hand to squish the potato down to about 1/2 inch thick. Put the smashed potatoes on a baking sheet covered in aluminum foil and then a layer of parchment paper if you have it. Sprinkle on Olive Oil and salt or salt substitute. They get cooked in a 425 oven for 30 minutes.
Next we prepared the brussel sprouts. I used frozen brussel sprouts - much easier. Just toss them with some olive oil, balsamic vinegar and a little pinch of salt or salt substitute. The can cook in the same oven as the potatoes during the last 15 minutes. You could also use frozen asparagus but it will only take 5 minutes in the oven.
Now on to the fish. The fish cooks at 350 for 15 minutes or so. The rule is 10 minutes per inch of thickness of the fish. All I do is smear some Laughing Cow light cheese on the top. If you don't have this then use light cream cheese. Want to shake it up some - use a flavoured light cream cheese like herb and garlic or vegetable! You only need about a Tablespoon per fillet. Lay a slice of prosciutto on top of each fillet. That's it. Put it in the oven. I have a toaster oven so I used it to cook the fish while the potatoes and brussel sprouts were in the big hotter oven. Once the fish was done I topped it with some shredded parmesan cheese and a sprinkle of fresh basil which I had on hand. It's optional.