Step 1: Preheat your oven to 350°F (175°C). Grease a 9x13 inch baking dish.
Step 2: In a large bowl, combine ½ cup of the melted butter, brown sugar, corn syrup, eggs, and vanilla extract. Whisk until well combined and smooth.
Step 3: Stir in the pecans until they are evenly coated. Pour this pecan mixture into the prepared baking dish, spreading it into an even layer.
Step 4: In a separate medium bowl, whisk together the all-purpose flour, granulated sugar, baking powder, and ground cinnamon.
Step 5: Add the milk and the remaining ½ cup of melted butter to the dry ingredients. Stir just until combined and no dry streaks of flour remain. Do not overmix.
Step 6: Carefully pour the cobbler topping mixture evenly over the pecan filling in the baking dish. Do not stir or mix the layers together.
Step 7: Bake for 45-55 minutes, or until the topping is golden brown and the filling is bubbly and set. A toothpick inserted into the topping should come out clean.
Step 8: Remove from the oven and let cool for at least 15-20 minutes before serving. This allows the filling to set further.