Preheat the oven to 350°F (175°C) and prepare the heart-shaped cake pan by greasing and flouring it.
In a mixing bowl, whisk together flour, baking powder, and salt. Set aside.
1 ½ cups All-purpose flour, 1 ½ tsp Baking powder, ¼ tsp Salt
In a separate large bowl, cream butter and sugar until light and fluffy.
½ cup Unsalted butter Softened, ¾ cup Granulated sugar
Add eggs one at a time, beating well after each addition. Mix in vanilla extract.
2 Large eggs Room temperature, 1 tsp Vanilla extract
Alternately add dry ingredients and buttermilk to the batter, starting and ending with dry ingredients. Mix until just combined.
½ cup Buttermilk Room temperature
Stir in pink food coloring until evenly incorporated.
2-3 drops Pink food coloring
Pour batter into the prepared heart-shaped pan and smooth the top.
Bake for 30 minutes or until a toothpick inserted in the center comes out clean.
Let the cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
In a bowl, beat butter until creamy, then gradually add powdered sugar, heavy cream, vanilla, and pink food coloring. Beat until smooth and fluffy.
1 cup Unsalted butter Softened, 3 cups Powdered sugar Sifted, 2 tbsp Heavy cream, 1 tsp Vanilla extract, 1-2 drops Pink food coloring
Apply a crumb coat to the cooled cake, then frost evenly with buttercream using an offset spatula.
Fill a piping bag with frosting and decorate the edges with vintage-style piping.
Serve the cake on a decorative cake stand and garnish with optional edible glitter or fresh berries.