Prepare the Oven and Baking Dish: Preheat oven to 375°F. Butter a 7x10 baking dish that is at least 2 ½ inches high to prevent overflow during baking. This preparation ensures your cobbler will bake evenly and won't make a mess in your oven.
Make the Pecan Pie Filling: In a large bowl, combine corn syrup, vanilla extract, ground cinnamon, eggs, light brown sugar, chopped pecans, ground allspice, and kosher salt. Mix thoroughly until all ingredients are well incorporated. The mixture should have a smooth consistency with the pecans evenly distributed.
Transfer Filling to Baking Dish: Pour the pecan pie filling mixture into the prepared baking dish, spreading it evenly. Use a spatula to ensure the filling reaches all corners of the dish.
Prepare the Dry Ingredients for Topping: In a separate bowl, mix together the flour, baking powder, ground cinnamon, sugar, and kosher salt. Whisk well to ensure even distribution of the leavening agents and spices.
Incorporate the Butter: Cut the cold butter into the dry mixture using a pastry cutter or two knives until the mixture resembles pea-sized crumbs. This technique creates a flaky, tender cobbler topping.
Complete the Cobbler Topping: Add the vanilla extract, buttermilk, and chopped pecans to the flour-butter mixture. Stir until just incorporated, being careful not to overmix. The dough should be sticky and slightly lumpy.
Add Topping to Filling: Using a large spoon or ice cream scoop, drop equal-sized portions of the cobbler dough on top of the pecan pie filling. The cobbler will spread during baking, so you don't need to cover the entire surface.
Bake the Cobbler: Bake in the preheated oven for 40-45 minutes, or until the cobbler topping is golden brown and the filling is set but still slightly jiggly in the center. The filling will continue to set as it cools.
Cool and Serve: Remove from the oven and allow to cool slightly before serving. This dessert is delicious on its own or served with a scoop of vanilla ice cream.