Preheat oven to 450 °F. Line a baking sheet with foil. Set a rack on top and coat it with cooking spray.
Combine gingersnap crumbs, oil and butter in a shallow dish, crumbling with your fingertips until well blended; set aside. Whisk together egg white, brown sugar and lemon juice in a medium bowl; set aside.
Peel bananas and trim pointed tips. Cut bananas into 3/4-inch rounds. Dip about 6 banana pieces into the egg white mixture, then, with 2 forks, transfer them to the crumb mixture. Roll the banana pieces in the crumbs with 2 clean forks until evenly coated. Place on the prepared rack. Repeat with the remaining bananas.
Bake until crisp, golden and heated through, about 8 to 12 minutes. Arrange the hot "scallops" on dessert plates, garnish with lemon wedges and mint sprigs and pass the Ginger-Yogurt Cream separately.