Preheat the oven to 350°F (175°C) and grease a donut cake pan.
In a large bowl, cream together the butter and sugar until light and fluffy.
Add the eggs one at a time, mixing well after each addition.
Stir in the vanilla extract and buttermilk until combined.
In another bowl, whisk together the flour, baking powder, baking soda, and salt.
Gradually add the dry ingredients to the wet mixture, mixing until just combined.
Pour the batter into the prepared donut cake pan, smoothing the top.
Bake in the preheated oven for 30-35 minutes or until a toothpick comes out clean.
Let the cake cool in the pan for 10 minutes before transferring it to a wire rack.
Once cooled, frost with pink frosting and top with fresh berries and sprinkles.