Rub butter into flour in a bowl using your fingers until evenly combined. Add sugar, baking powder, and salt to flour mixture; make a well in the center. Mix pumpkin and egg together in a separate bowl; pour into the well and mix until dough is well combined. Turn dough onto a floured work surface and cut into squares using a knife with flour on it. Arrange squares on a baking sheet.
Bake in the preheated oven until lightly browned, 15 to 20 minutes.
