01 - Preheat oven to 350°F. Grease a 13x18-inch rimmed baking sheet and line with parchment paper for easy release.
02 - In a large mixing bowl, whisk the melted butter and granulated sugar until well blended. Add the eggs and vanilla extract; beat until smooth and creamy.
03 - In a separate bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt until evenly distributed.
04 - Add half of the dry mixture to the wet ingredients, followed by half of the milk; mix gently until just combined. Repeat with the remaining dry mixture and milk, mixing only until smooth.
05 - Gently fold the chopped pecans into the batter, ensuring even distribution throughout.
06 - Transfer the batter to the prepared baking sheet, spreading it evenly with an offset or silicone spatula. Bake for 20 to 25 minutes, or until a toothpick inserted in the center yields no wet batter.
07 - While cake bakes, melt butter and packed light brown sugar in a saucepan over medium heat, stirring until sugar has dissolved, about 2 to 3 minutes. Add milk and bring to a gentle boil for 1 minute. Remove from heat, whisk in vanilla extract, then gradually add sifted powdered sugar, whisking until glaze is smooth.
08 - Pour warm caramel glaze evenly over the hot cake immediately after baking. Sprinkle with the remaining chopped pecans.
09 - Allow the cake to cool thoroughly before slicing into squares and serving.