Preheat the oven to 350°F (175°C). Grease and flour three 8-inch cake pans.

In a large bowl, cream butter and sugar until fluffy. Add eggs one at a time, beating well after each addition.

In a separate bowl, sift together flour, baking powder, baking soda, and salt.

Alternate adding dry ingredients and buttermilk to the creamed mixture, starting and ending with the dry ingredients. Stir in vanilla extract.

Divide the batter evenly among the pans and bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean. Cool completely.

In a saucepan, combine raspberries, sugar, cornstarch, and lemon juice. Cook over medium heat, stirring constantly, until thickened. Remove from heat and let it cool.

Heat heavy cream in a small saucepan until just below boiling. Remove from heat and pour over white chocolate chips in a bowl. Let sit for 2 minutes, then stir until smooth. Chill until slightly thickened but still spreadable.

Place one cake layer on a serving plate. Spread half the raspberry filling over the top. Add the second cake layer and spread the remaining filling. Place the third layer on top.

Frost the cake with white chocolate ganache, spreading it evenly over the top and sides.

Garnish with fresh raspberries and white chocolate shavings, if desired. Chill the cake for 1-2 hours before slicing.

For an extra moist cake, brush the layers with a simple syrup before assembly.

Use high-quality white chocolate for a richer ganache.

The raspberry filling can be made a day ahead for convenience.