Preheat the oven to 425℉. Line 2 large baking sheets with parchment paper.

In a large mixing bowl, whisk together the flour, brown sugar, baking powder, baking soda, salt, and cinnamon. Using a pastry cutter, work in the cold cubes of butter until the pieces of butter are the size of peas.

In a separate bowl, whisk together the pumpkin puree, milk, and egg until fully incorporated. Add to the flour/butter mixture and mix until a dough begins to form.

Turn the mixture onto the countertop and gently knead and fold the dough to laminate and bring the dough together. Sprinkle flour on the countertop and use a rolling pin to roll out the dough into a rectangle about 15"x12".

Cut the dough into 18 rectangular or square-shaped biscuits and arrange on the prepared baking sheets, leaving room between each biscuit.

Bake in the preheated oven for 10-12 minutes or until the tops are golden-brown and the biscuits have risen. Let cool for about 5 minutes before serving while still warm.