In a small bowl, soak dried mushrooms in 1/2 cup hot water for 15 minutes.
Meanwhile, heat oil in a large saucepan over medium heat. Add shallots and garlic and cook 1 minute. Add fresh mushrooms and cook 3-5 minutes, until they begin to release juice. Add pastina and sage and cook 1 minute.
Add 1/2 cup of the broth and simmer until the liquid is absorbed.
Continue adding broth, 1/2 cup at a time, waiting until liquid is absorbed before adding more. (Total cooking time should be about 8 minutes.)
Strain reconstituted mushrooms through a paper-towel-lined sieve, reserving the liquid. Rinse mushrooms to remove any dirt and slice into thin strips.
Add mushrooms to pastina. Using a tablespoon, add most of the reserved liquid from the mushrooms to pasta. (Do not use the liquid at the very bottom of the cup, because it will have sediment.)
Simmer until liquid is absorbed. Stir in Parmesan and cook 1 minute, until cheese melts. Remove from heat and stir in parsley. Season to taste with salt and black pepper. Serve immediately.
Nutritional information includes 1/8 teaspoon of added salt per serving.