These wonderfully unusual biscuits can be made a day ahead. I've never met anyone of any age who didn't love them.
Preheat the oven to 400 degrees. Grease a cookie sheet or line it with a piece of parchment paper.
In a large bowl, stir the flour, brown sugar, baking powder, salt and spices. (You may need to crumble in the brown sugar with your fingers.) With a pastry blender or two knives, cut in the butter until the mixture looks like cornmeal. Stir in the pumpkin, and mix until a soft dough forms.
On a well-floured surface, with well-floured hands, pat out the dough to 1/2-inch thickness. Using a floured, sharp knife, cut out 2-inch-square biscuits. Place them on the cookie sheet, and put it on the middle rack of your oven. Bake the biscuits for 15 to 20 minutes (because they're already brown, you may need to break one open to see if they're done). Serve hot or at room temperature. Makes 16 to 18 biscuits.