Tosfot in Pesachim 30a paragraph Amar Rava quotes a rule from the Halachot Gedolot from Spain.
ובה"ג של אספמיא פסק דחתיכה בחתיכות בנ"ט ומייתי מדרבא בפ' גיד הנשה
The Tosfot in Chulin 97a quotes the same BHG from Spain. What is this book? From what is it different from the standard BHG?
It's important to note that the Tosfot quotes a lot of Geonic sources that he doesn't identify with the BHG from Spain: (from the Tosfot in Chulin):
Seder Tanayim Veamorayim;
Sheiltot Derav Achay;
Teshuvat Hageonim, quoting RY Tov Elem (Bonfils);