Spread the foil and put the asparagus on it, in general, asparagus can be replaced with any frozen vegetables (beans, broccoli, etc.)
Season with salt, pepper, sprinkle with rosemary, cut three slices from half a lemon and put them on the fish, and squeeze the juice from the rest of the lemon onto the fish.
Close the foil, but do not wrap it too much. Put in an oven heated to 180-200 degrees
After 20 minutes, you can take it out. The sauce is absolutely any, I often make just bechamel, my husband sometimes asks for a creamy mushroom-in general, everything is optional)))