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.
Professional Recipe: This recipe was provided by a chef, restaurant or culinary professional and makes a large quantity. The Food Network Kitchens chefs have not tested this recipe in the proportions indicated and therefore cannot make any representation as to the results.
Recipe courtesy Chef Mark Peterson, Pump Room Restaurant, Bath England