Grate pumpkin on the medium sized grater or in the food processor. Transfer to a large bowl.
Add juice of 1 lemon, 1 tbsp of pumpkin spice, 1 tbsp of vanilla, 1/2 cup of sugar, and eggs. Combine.
In a separate bowl, mix flour, farina, 1/2 cup of sugar, and salt. Cut in butter until mixture resembles coarse crumbs.
Divide flour mixture into 3 parts.
Butter and flour a 9x13 inch baking pan.
Place one part of flour mixture on the bottom of the pan, do not press.
Add a layer of the pumpkin mixture, approximately half.
Add the second part of the flour mixture.
Top with the rest of pumpkin. Gently sprinkle the remainder of flour/butter mixture.
Place pan in the preheated oven at 350°F for approximately 40 minutes.
To check if the pie is done, take a toothpick and insert it into the center of the cake. If it comes out clean, or with a few moist crumb, this pie is done. Otherwise, you are going to need to add more baking time.
Once fully baked, let it cool to room temperature before serving.