POSITION rack in centre of oven, then preheat to 300F. Line a large baking sheet with parchment paper. Stir flour with baking powder and salt in a medium bowl.
USING an electric mixer on medium, beat sugar with butter in a large bowl until fluffy, 1 to 2 min. Beat in egg, orange zest, cream and food colouring. Stir in flour mixture until combined. Roll dough into a large ball. Flatten into a disc and cut into 8 wedges. Roll each wedge into a ball and arrange on prepared sheet, 2 in. apart.
BAKE until tops are just cracked and puffy, 22 to 23 min. Remove from oven and let stand until rounds are cool enough to touch, about 10 min. Reduce heat to 275F. Cut each round into 4 wedges. (They should resemble orange wedges.) Lay wedges, cut side down, on same sheet. Continue baking until wedges are very firm but not yet golden, 23 to 25 more min. Transfer to a rack to cool completely.