Preheat oven to 350. Prepare three 8 inch cake pans by spraying with baking spray, lining the bottom with a parchment circle, and then lightly spraying again with baking spray.
Combine cake flour and baking powder. Set aside.
Cream together butter and sugar until light and fluffy. Add the eggs one at a time and mix well between each addition. Add the vanilla seeds and vanilla. Mix until incorporated.
Alternately add the milk and the flour mixture, starting and ending with the flour. Don't overmix!
Pour your batter into your cake pans and bake for 25-30 minutes, or until a cake tester comes out with moist crumbs. Let cool in pan for 10 minutes. Remove from pans and cool on wire racks completely.
Buttercream:
Mix together all ingredients until light and fluffy.
Raspberry Filling:
Place berries and sugar into a sauce pan over medium low heat. Cook until liquid is released and sugar is dissolved, about 15 minutes.
Take the berry mixture and press through a fine metal strainer. On occasion, with a different spoon, scrape the bottom of the strainer to remove any stubborn pulp that is sticking there.
Put back into a now cleaned out saucepan. Add Chambord, water, and vanilla. Stir well and simmer over low heat for another 10 minutes.
Combine cornstarch and water into a slurry. Drizzle into the simmering raspberry sauce while stirring. Simmer gently until thickened. Let cool completely.
Assembly:
Pipe a thick line of buttercream around the edges of two cakes. Gently spread filling inside. Place both layers in the fridge for 30 minutes. Gently place cakes on top of each other, and frost with buttercream. Garnish with raspberries.