Preheat the oven to 350F degrees.
Butter and flour a 9x13 inch cake pan.
In a medium bowl whisk together the flour, pumpkin spice, cinnamon, baking powder, baking soda and salt.
In a separate large bowl beat together the oil, sugar, eggs and vanilla extract. Turn the mixer to low speed and beat in the pumpkin puree and Greek yogurt.
Carefully beat in the flour mixture, turning off the mixer and scraping down the sides of the bowl as necessary.
If using frozen cranberries, toss them in 1 tablespoon of flour. Then fold the cranberries into the cake batter using a large spatula.
Pour the batter into the prepared pan and bake for 38-42 minutes, or until an inserted toothpick comes out clean.