Preheat your oven to 350°F (175°C).
In a large bowl, combine the flour and salt.
Cut in the chilled butter until the mixture resembles coarse crumbs.
In another bowl, whisk together the sugar, eggs, and pumpkin puree.
Add the vanilla extract, cinnamon, and nutmeg, mixing well.
Gradually fold the wet ingredients into the dry mixture.
Stir in the nuts if using.
Pour the batter into a greased baking dish.
Bake for 45 minutes or until a toothpick comes out clean.
Allow to cool for 10 minutes before serving.