So they were pre-soaked, then. What I'd probably do is cover them for part of the cooking time, then uncover them and let them get crunchy at the end.
I remember a recipe for baked, sliced potatoes that gave me similar problems. You were supposed to peel, slice, oil, season and bake them uncovered. Sounded delicious, but when I followed directions, they turned out like hockey pucks. Never did figure out what was doing wrong. *shrug*
I got it out of Food Network magazine and it was a very abbreviated recipe. It was in one little block of a calendar.
I searched for more recipes and most state a lower baking temp, 350 for 45 mins. Plus they say to drain and rinse them and pat them dry with paper towel, toss them with the oil and seasoning after they're done baking.
And it lists more flavor recipes!
Seasoning Suggestions (add more or less if you like, these are just guidelines)
1 ½ pounds thinly sliced mushrooms
2 ½ teaspoons salt
3 oz dried mushrooms (morels, porcini or cepes)
3 ½ cups water
2 cups thinly sliced onion
1 tablespoon chopped garlic
1 tablespoon whole black peppercorns
½ teaspoon celery seed
¼ teaspoon dried red pepper flakes
2 teaspoons dried thyme
1 teaspoon dried basil
3 bay leaves
¼ cup malt or cider vinegar
-Layer the sliced mushrooms in a nonreactive pot (ceramic, stoneware), salting each layer. Cover the pot and leave it in a cool place for about six hours.
-Put everything else except the vinegar in a pot, bring to a boil, then simmer for ½ an hour
-Add the salted mushrooms and bring the ketchup to a rolling boil for 15 minutes
-Strain the ketchup through a wire strainer; discard the solids
-Add the vinegar and reboil the ketchup for 2-3 minutes
-Strain the ketchup again through several layers of cheesecloth (or a coffee filter) and then bottle/jar the ketchup.
There are lots of other recipes and variations of seasonings if you google (some call for mace and allspice, and even brandy, for example), but this one was most appealing to me. I gather that it was adapted from a Bill Neal recipe in Southern Cooking.
There is a wealth of information on danceforums on non-dancing topics. I can't recall if it was in this thread or not, but I still use a recipe from Peaches for foil-roasting parsnips/carrots that even my nephews like.