Preheat oven to 350° °F.
Line bottom of two 8 or 9 inch cake pans with parchment paper. Spray pans with cooking spray and flour or butter and flour.
Sift together flour, cocoa, baking powder and baking soda in medium bowl.
Whisk in sugar and salt. Set aside.
In another mixing bowl, add buttermilk, vegetable oil, vanilla and eggs. Whisk until combined.
Gradually whisk dry ingredients into wet ingredients.
Pour batter evenly into cake pans.
Bake for 30-35 minutes if using 8" pans or 25-30 minutes if using 9" pans. Toothpick inserted in center of cake should come out with few moist crumbs.
Score edges and cool cakes in pans for 10 minutes.
Flip cakes onto wax paper and cool completely on cooling racks.
Cut cakes in half to make 4 discs.
Place on serving platter.
Insert small wax paper squares under bottom edges of first layer of cake to keep platter clean while decorating.
Add 1/3 of raspberry jam on first layer and spread evenly. Repeat with 2 additional layers.
Top with final layer.
Spread whipped ganache over top and sides of cake.
Refrigerate for 6 hours or overnight.
Remove cake from refrigerator for final chocolate ganache.
Run tip of squeeze bottle filled with warm chocolate ganache along top edge of cake. Gently squeeze bottle and release to create drips along edges. longer you rest dip and squeeze, longer drips.
After drips along edges are complete, squeeze remaining ganache in center of cake. Spread evenly.
Refrigerate cake until ready to serve. Serve at room temperature.
Refrigerate in sealed container for up to 5 days.