I had a full-course meal of crab at a restaurant that specializes in crab.
この場合、次のような言い方ができますよ。
ーI had a full-course meal of crab at a restaurant that specializes in crab.
「カニ専門店でカニ料理のフルコースを食べました」
a full-course meal of crab で「カニ料理のフルコース」
a restaurant that specializes in crab「カニ専門店」
ご参考まで!