Preheat your oven to 350°F (175°C). Grease and flour your heart-shaped cake pan(s), then line the bottom with parchment paper cut to match the heart shape.
In a medium bowl, whisk together the sifted flour, baking powder, and salt. Set aside.
2¾ cups All-purpose flour Sifted, 2½ teaspoons Baking powder, ½ teaspoon Salt
Using an electric mixer, cream the softened butter and sugar until light and fluffy, about 3-5 minutes.
1 cup Unsalted butter Softened to room temperature, 1¾ cups Granulated sugar 350g
Add the eggs one at a time, beating well after each addition. Then beat in the vanilla extract until fully incorporated.
4 Large eggs At room temperature, 2 teaspoons Pure vanilla extract Or vanilla bean paste for stronger flavor
Alternately add the dry ingredients and milk to the wet ingredients, beginning and ending with dry (⅓ dry, ½ milk, ⅓ dry, ½ milk, ⅓ dry). Mix on low speed until just combined, being careful not to overmix.
1 cup Whole milk At room temperature
Pour the batter evenly into your prepared heart-shaped pan(s). Use your spatula to smooth the top(s) for even baking.
Bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean. The cake should spring back lightly when touched.
Let the cake(s) cool in the pan(s) on a wire rack for 10-15 minutes. Then invert onto the rack to cool completely before frosting.
For the frosting, beat the softened butter with an electric mixer until smooth and creamy, about 2-3 minutes.
1½ cups Unsalted butter Softened to room temperature
Gradually add the sifted powdered sugar, mixing on low speed until incorporated. Then increase speed and beat until light and fluffy (3-5 minutes).
5-6 cups Powdered sugar Sifted
Beat in the vanilla extract and salt to enhance the flavor profile.
2 teaspoons Pure vanilla extract, 1 pinch Salt To balance sweetness
Add heavy cream or milk, one tablespoon at a time, until you reach your desired consistency. The perfect buttercream should be smooth and spreadable but still hold its shape.
3-4 tablespoons Heavy cream or milk Adjust for consistency
Add pink gel food coloring, a tiny drop at a time, mixing well after each addition until you achieve your desired shade of pink.
Pink gel food coloring As needed for desired shade
If making a layer cake, level the cooled cake layers using a cake leveler or serrated knife.
Place the bottom layer on a serving plate or cake stand. For stability, add a small dollop of frosting underneath.
Apply a generous layer of pink buttercream on top of the bottom layer, spreading evenly with an offset spatula.
Place the second layer on top (if applicable), making sure it's properly aligned with the bottom layer.
Apply a thin "crumb coat" of frosting over the entire cake. Chill for 15-30 minutes to set this base layer.
Apply the final, thicker layer of pink buttercream, smoothing with an offset spatula. For a smoother finish, dip your spatula in hot water and wipe dry between strokes.
Decorate as desired with piped buttercream designs, sprinkles, or other embellishments.