In the Movie entitled "In a World" a father invites his 2 daughters for a dinner which his girl friend has cooked. While one of the daughters is eating she asks about one of the dishes. Her father's friend says " they're just cherries from a can." Then the father says "from Canter's", so his girl friend says "no, I made it." The father then says "Just kidding. It's as Jewish as you can get in her family." So, she laughs and says "That's a good one." What does he mean by "It's as Jewish as you can get in her family"?