I found this but I think it’s for a very large amount:
Finally sweet-talked a waitress into getting it for me.
Mushroom Seasoning:
2 cups granulated garlic
1/2 cup sugar
1/2 cup black pepper
3/4 cup onion salt
1/4 cup salt
Be really light with this stuff. Very strong. Sauteed some baby bella mushrooms, then added this seasoning to it-> perfect.
Ha, funny!