Preheat the oven to 350°F (175°C). Grease a 9-inch round cake pan.
Melt the butter in a small saucepan over low heat. Stir in the brown sugar, and pour this mixture into the bottom of the greased pan.
Evenly distribute fresh cranberries over the butter and brown sugar mixture in the pan.
In a mixing bowl, cream together the granulated sugar and eggs until light and fluffy. Mix in the vanilla extract.
In a separate bowl, combine the flour, salt, and baking powder. Gradually add this mixture to the creamed mixture, alternating with the milk.
Pour the batter over the cranberries in the pan, ensuring it covers them evenly.
Bake for 35-40 minutes or until a toothpick inserted into the center comes out clean.
Let the cake cool for about 10 minutes, then invert onto a plate to reveal the mesmerizing cranberries topping.