01 - Preheat oven to 375°F (190°C) and lightly grease a 2-quart baking dish.
02 - In a large mixing bowl, combine sliced pears with granulated sugar, brown sugar, lemon juice, cinnamon, ginger, nutmeg, allspice, salt, cornstarch, and vanilla extract. Toss thoroughly to coat fruit with the seasonings.
03 - Transfer the spiced pear mixture into the prepared baking dish, spreading evenly.
04 - In a separate bowl, whisk together all-purpose flour, granulated sugar, baking powder, ground ginger, cinnamon, and salt.
05 - Add cold cubed butter to the flour mixture. Cut in with a pastry cutter or fork until the mixture resembles coarse crumbs.
06 - In a small bowl, whisk together whole milk and egg. Pour into the dry mixture and gently stir just until combined. Fold in crystallized ginger if using, being careful not to overwork the dough.
07 - Drop spoonfuls of biscuit dough over the pear filling, covering most of the surface without pressing down. Sprinkle with coarse sugar if desired.
08 - Bake in the preheated oven for 35 to 40 minutes, until biscuits are golden and the filling is bubbling around the edges.
09 - Allow to cool slightly before serving. Enjoy warm with vanilla ice cream or whipped cream if desired.