* 2 1/2 cups all-purpose flour * 2 tablespoon baking powder * 1/8 teaspoon allspice * 1/8 teaspoon ground cloves * 1/2 teaspoon salt * 1/4 cup packed light brown sugar * 1/4 cup unsalted butter, chilled * 1/4 cup shortening, chilled * 1 1/2 cups sweet potatoes, mashed * 2 tablespoons soy milk
Heat oven to 425 degrees Fahrenheit (218.3 degrees Celsius). Sift the flour, baking powder, allspice, cloves and salt in a large bowl. Use the tips of your fingers to blend in the brown sugar.
Cut in the chilled butter and shortening with a pastry cutter or pulse in a food processor until the mixture resembles coarse, crumbly meal. Then, stir in the mashed sweet potatoes and knead until the dough just holds together.
Turn the dough onto a lightly floured surface. Knead gently for 1 minute, adding a little flour as necessary to incorporate all the ingredients.
Pat the dough in a 1/2-inch (1.27-cetimeter) circle and let it rest, covered with a clean towel, for 10 to 15 minutes.
Cut out the biscuits with a 2-inch (5.08-centimeter) round cutter dipped in flour. Gather the scraps, pat out again and cut into biscuits. Arrange them about 3/4 of an inch (1.905 centimeters) apart on an ungreased baking sheet and brush the tops with milk. Bake until golden brown – 10 to 12 minutes. Cool the biscuits on a rack.