Preheat the oven to 425 degrees F.
In a small saucepan, cover the squash with cold water, bring to a boil and simmer until tender, about 10 minutes. Drain and place back into empty hot saucepan to dry the squash. It is very important to drain well. Mash with a potato masher and drain again if necessary.
Sift the flour, baking powder and ginger into a large bowl. Rub the butter into the flour mixture until the mixture resembles bread crumbs. Add in the sugar, mashed squash and 2 tablespoons of milk. Combine gently with a wooden spoon. Add more milk only if necessary to make a soft dough. Turn it out onto floured board and press down lightly to a thickness of about 1-inch. Using a large scone or biscuit cutter, flour the cutter and cut out the scones and place on a lightly greased baking tray.
Using a sieve, dust scones with flour. Bake for about 12 to 15 minutes or until well-risen and golden brown.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Mark Peterson, Pump Room Restaurant, Bath, England