Preheat oven to 340 degrees F. Butter and flour three 6-inch pans.

Sift the flour, salt, baking soda, and baking powder into a large bowl; whisk together and set aside.

Beat the wet ingredients together in a medium bowl; add lemon zest.

Combine wet and dry ingredients, mix until just combined. Fold in dried raspberries.

Divide the mixture evenly into the cake pans and bake for about 30 minutes or until centers are springy to the touch.

For the White Chocolate Buttercream: In a small saucepan over medium low heat, combine raspberries, lemon juice, lemon zest, and sugar. Mash and heat for a minute, then bring to a simmer. Simmer until reduced by half, about three minutes. Strain and chill.

In a stand mixer, cream the butter. Add confectioners sugar and salt; beat until creamy. Mix in melted and cooled white chocolate.

Divide batter in half. Add vanilla to one batch and 2 1/2 tbsp of the raspberry reduction to the other. Adjust consistency with more confectioners sugar if needed. Transfer both batches to separate piping bags.

For the Italian Buttercream: Beat egg whites, salt, and cream of tartar. Slowly add in 1/3 cup of sugar until soft peaks form.

Combine remaining sugar and 1/3 cup water in a saucepan; heat until clear. Drizzle hot sugar into the meringue.

Continue beating until meringue is cool. Add butter one tablespoon at a time, then add salt and vanilla, if using. Beat until silky.

Divide into five bowls. Keep one bowl white and color the others for gradient.

Line up printable heart sheets and cover with parchment. Microwave candy melts, transfer to piping bag, and pipe hearts according to stencil.

Chill hearts until hardened.

For assembly: Pipe the pink/white chocolate buttercream between each cake layer. Cover cake with a thin crumb coat and chill for 10-15 minutes.

Once chilled, apply the Italian buttercream gradient from white to pink. Smooth with an offset spatula and add hearts.