In a large bowl, whisk together the brown sugar, granulated sugar and eggs until incorporated. Stir in the butter, vanilla, lemon zest and juice, milk, flour and 1 cup chopped pecans until combined. Pour the mixture into the unbaked pie shell. Arrange the pecan halves on top of the pie in a circular pattern.
Bake until the crust is golden brown and the filling is set but still a little loose in the center (it will set as it cools), about 55 minutes. Serve warm or at room temperature.