In a large bowl, whisk together the flour, brown sugar, baking powder, cinnamon, salt, ginger, cloves, all spice, and nutmeg.
Add the frozen & cubed butter and cut in with a pastry cutter until butter is dispersed and only pea-sized chunks remain. If needed, use fingertips to rub any bigger chunks of butter into the flour.
In a separate bowl, whisk together the canned pumpkin, 1/2 cup (4 1/8 ounces) cream, and vanilla extract. Add to flour mixture and fold in until the dough starts to come together; it will still be crumbly at this point.
Use your hands to finish bringing the dough together into a ball. It will take some time for it to all come together and at first it might look like it needs more liquid. Be patient with it, and if the dough definitely seems too dry to come together, add the remaining 1/4 cup (2 ounces) cream a tablespoon at a time, as needed. You may not need to use it all. Also be careful not to overwork the dough; stop as soon as it comes together. You may need to turn it out onto a sheet of parchment (see step 5) to get the last bit of crumbs incorporated.
Line a baking sheet with parchment paper and transfer dough to parchment. Use your hands to flatten into a round about 1” thick. Transfer to freezer and freeze for 1 hour.**
Towards the end of the chilling time, preheat your oven to 400ºF with a rack in the center position. Remove the chilled scones from the freezer and slice into 8 equal pieces (like you would a pizza). A bench scraper works well here. Space the scones apart on the baking sheet.
Bakes scones in preheated oven for 15-18 minutes, until a toothpick inserted into the center of one comes out clean. Allow to cool to room temperature before glazing.
Melt the butter in a medium microwave-safe bowl. Whisk in milk.
Add confectioner’s sugar, vanilla extract, cinnamon, salt, nutmeg, ginger, all spice, and cloves. Whisk until smooth.
Spoon glaze over cooled scones, letting glaze drip down sides a bit. Allow glaze to set.
Scones are best served the day they are baked (see notes), but leftovers can be stored in an airtight container or zip-top bag in the refrigerator. Reheat briefly in the microwave (about 30 seconds) before serving.
*Prep time includes chilling time.
**Make Ahead: If you want to freeze the scones for a longer period before baking, you can! Remove them from the freezer after an hour, slice them into triangles as described in step 6, and place in an airtight zip-top bag. Then you can return them to the freezer. When ready to bake, remove scones from the freezer and transfer to a parchment-lined baking sheet. Allow to thaw slightly while preheating your oven. Baking time will probably be closer to 18 minutes; look for a toothpick to come out clean.