Preheat oven to 375°F.
Prepare the filling. Add peeled pears to a bowl along with brown sugar, sugar, cinnamon, nutmeg, allspice, pure vanilla extract, lemon juice, cornstarch, water. and melted butter. Mix until well-combined. Pour into buttered 9-inch cast iron skillet.
Prepare the topping. In a separate bowl, add flour, sugar, cinnamon, nutmeg, baking powder, lemon zest and salt and whisk to mix dry ingredients.
Add cold, cubed butter to the flour mixture. Blend with flour using a pastry blender until butter is pea-sized. Add buttermilk and stir just until combined.
Assemble topping and bake. Add topping by the spoonful. Leave some openings in the cobbler topping (this allows steam to release and helps with caramelize the filling). Bake until golden brown, ~40 minutes. Check after 30 minutes.
Enjoy with a scoop of vanilla bean ice cream. Cobbler is best eaten when warm.
