Rinse trout and pat dry.
Place in 12 x 7 x 2-inch microproof baking dish.
Place butter in 2-cup glass measure.
Cook on HI, 1 minute.
Add mushrooms, carrots, bread crumbs, tarragon, and pepper.
Stir until well mixed.
Stuff mushroom mixture into trout cavities.
Sprinkle lemon juice over trout.
Cover with waxed paper and cook on HI, 6 minutes.