Preheat your oven to 350°F (175°C). Grease your baking dish thoroughly with butter or cooking spray and dust it lightly with flour.

Cream softened butter and granulated sugar in a large mixing bowl on medium-high speed for 3 to 4 minutes.

Add eggs one at a time, mixing well after each addition.

Whisk together the flour, baking soda, baking powder, and salt in a separate bowl.

With the mixer on low, alternate adding dry ingredients and buttermilk to the butter-egg mixture, finishing with dry ingredients.

Pour batter into the prepared pan and tap gently to release air bubbles.

Bake for 35 to 45 minutes, until a toothpick comes out clean or with a few moist crumbs.

Melt ½ cup unsalted butter in a saucepan over medium heat. Add brown sugar and bring to a gentle boil, stirring constantly.

Pour in whole milk and boil for exactly 1 minute. Remove from heat and whisk in powdered sugar and vanilla extract until smooth.

Pour the warm caramel icing over the warm cake and let it set for 15-20 minutes before slicing.