Preheat oven to 375°F (190°C) and grease a 13×9-inch baking dish.

In a medium bowl, combine chopped pecans, brown sugar, and ground cinnamon for the filling and topping. Set aside.

In a large bowl, cream butter and sugar until light and fluffy. Add eggs one at a time, mixing well after each.

Mix in sour cream, lemon zest, and vanilla extract.

In a separate bowl, whisk together flour, baking powder, baking soda, and salt.

Gradually mix the dry ingredients into the wet mixture, just until combined. Do not overmix.

Spread half the batter evenly into the prepared pan. Sprinkle half of the pecan filling over the batter.

Drop remaining batter over the filling and gently spread it. Top with the remaining pecan mixture.

Bake for 24–28 minutes or until a toothpick inserted into the center comes out clean.

Allow to cool for at least 20 minutes.

For the glaze, whisk powdered sugar with milk until smooth. Drizzle over the cooled cake.

Serve warm or at room temperature.