Line a half sheet pan with parchment paper and set aside.
Place the flour, cinnamon, nutmeg, cloves, ginger, baking powder, salt and sugar in a large bowl. Whisk to combine.
Add the cubed and chilled unsalted butter and toss to coat the butter pieces in flour.
Next, either cut the butter into the flour using a pastry cutter, or rub the butter into the flour. There should be some chickpea-sized pieces of butter coated in flour in the mix, and some coarse breadcrumb-sized pieces.
In a separate bowl, mix the pumpkin puree and half and half together until smooth. Add half of the liquid into the flour-butter mix, and use a fork to mix the liquid into the flour. There will be big clumps of wet dough.
Add the rest of the pumpkin mixture and stir it into the flour using a fork. When all the pumpkin mixture has been stirred in, there'll be a lot of wet clumps of dough. But there also may be some dry spots of flour too.
Turn the dough out onto a lightly floured parchment paper. Bring the dough pieces together to form a rough dough in the shape of a large circle or rectangle.
Use the parchment paper to help fold the dough over in half. Repeat again to fold the dough into quarters.
Then use the parchment paper to gently pat down the dough into a square or rectangle. Fold over in half again.
Lightly flour the dough, and flatten it out into a 6 x 9 inch rectangle.
Dip a sharp cookie cutter (2.5 - 3 in in diameter) in flour and cut out 6 scones from the dough. Clean and flour the cutter every time you cut out scones, so that you make nice and clean cuts. (To cut out scones, press the cookie cutter straight down into the dough without any twisting motion.)
Place cut scones on the parchment paper-lined baking tray.
Gather the dough scraps together, and gently pat it to form a dough that sticks together. Fold the dough over in half, and pat it again to a 6 x 4 - 5 inch rectangle. Cut out 3 scones from this, and place the scones on the parchment paper-lined baking tray.
Again, gather and pat the dough as before, then fold it over, and pat it to form a dough large enough to cut 2 more scones. Repeat again with the remaining dough scraps to cut one more scone. You should end up with a total of 12 scones.
Cover the baking tray with plastic wrap and freeze or refrigerate for at least 15 minutes. You can keep the scones in fridge overnight, OR keep them in the freezer for up to 3 months (see recipe notes on how to store them).
Before baking the pumpkin scones, preheat oven to 400°F / 200°C. Brush the tops of the scones with milk. Once the oven is preheated, remove the scones from the fridge/freezer, and bake in the preheated oven for 15 minutes, or until the tops are golden brown in color (20 minutes if baking from frozen).
Brush baked scones immediately with the brown butter glaze to let the glaze melt into the scones. OR let the scones cool down slightly first, if you'd like a glaze topping that doesn’t melt.