Melt the butter in a skillet over medium heat. Add the pears, sugar, flour, cinnamon, and salt, and stir to combine.

Continue cooking, stirring frequently, until the sugar has dissolved and the mixture is bubbly. Allow the mixture to bubble for 2 or 3 minutes, or until thickened.

Remove from heat. Stir in the vanilla.

Transfer the filling to a 1-quart baking dish. Set aside while you make the topping.

Combine the flour, brown sugar, baking powder, cinnamon, cardamom, ginger, allspice, nutmeg, and salt.

Add the butter, and mix with a pastry blender, a fork, or your fingers until the butter is about the size of peas.

Add about 3 tablespoons of the milk, and continue mixing the dough. Add the remaining milk, a small amount at a time, and mix just until the dough comes together.

Drop the dough by tablespoonfuls over the top of the filling. Sprinkle with sanding sugar, if using.

Place the baking dish on a lined, rimmed baking sheet to catch any potential spills.

Bake 30 to 35 minutes, or until the topping is browned and the filling is bubbly.

Serve warm or at room temperature.