Preheat your oven to 350°F (175°C). Grease and flour a heart-shaped cake pan, or line it with parchment paper for easy removal.

In a large mixing bowl, sift together the all-purpose flour, baking powder, baking soda, and salt. Set aside.

In another bowl, beat the softened butter and granulated sugar together until light and fluffy, about 3-4 minutes.

Add the eggs, one at a time, beating well after each addition. Stir in the vanilla extract.

Gradually add the dry ingredients to the wet mixture, alternating with the milk. Begin and end with the dry ingredients. Mix until just combined. If using sour cream, fold it into the batter for extra moisture.

Pour the batter into the prepared cake pan, spreading it evenly with a spatula.

Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out clean. Let the cake cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.

While the cake cools, make the frosting by beating the softened butter until creamy. Gradually add the powdered sugar, vanilla, and a pinch of salt. Add heavy cream or milk one tablespoon at a time until the frosting reaches your desired consistency.

Once the cake is completely cool, spread an even layer of frosting on top. You can also slice the cake in half horizontally to add a filling of frosting if desired.

Decorate the top of the cake with sprinkles, edible glitter, or heart-shaped candies for a festive touch.

Slice and serve your beautiful heart cake, perfect for sharing with loved ones!