Preheat oven to 350°F. Lightly grease a 2 or 3 quart baking dish. Set aside.
Whisk together pumpkin, evaporated milk, sugars, eggs, pumpkin spice, salt and butter in a large bowl until combined. Pour into prepared baking dish.
In a separate bowl, whisk the flour, sugar, baking powder, baking soda and salt together. In a small bowl, whisk butter, buttermilk and vanilla. Add to dry ingredients and stir just until combined.
Drop tablespoons of dough on pumpkin and bake for 45-55 minutes, or until dough is golden brown and no longer raw.