Preheat the oven to 350°F (175°C).

In a mixing bowl, cream together the butter and sugar until light and fluffy.

Add the eggs, milk, and vanilla extract, mixing until well combined.

In another bowl, whisk together the flour, baking powder, and cinnamon.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Pour half of the batter into a greased baking pan.

In a small bowl, mix together the brown sugar, cinnamon, and melted butter for the topping.

Sprinkle half of the topping mixture over the batter in the pan.

Pour the remaining batter on top and sprinkle with the remaining topping mixture.

Bake in the preheated oven for 30-35 minutes or until a toothpick inserted into the center comes out clean.