Yesterday, I tried making pumpkin pie recipe and I was surprised to see the color when I left it over for few hours. I donât have any idea that what have caused the pumpkin pie to turn green when it was baked and left over for few hours? I have used a spoon of baking powder in it. Do you think it could be the reason for the change in color? Does anyone have any idea about what has happened to my pie? Can you give me your favorite pumpkin pie recipe?