1. Preheat oven to 350.
2. Beat butter and sugar until fluffy, 5 min. Add eggs and beat well. Mix baking soda into flour, and then add in 3 batches on low speed, alternating with buttermilk. With mixer on lowest speed, stream in chocolate and vanilla. Beat until combined, scraping down pan to make sure it’s fully incorporated. Transfer to greased loaf pan and bake for 50 min, until skewer inserted in center comes out clean. For final 15 min of cook time, cover with foil to prevent top from burning.
3. Let cool in pan for 30 min, then transfer to wire rack and let cool completely. Pour chocolate ganache over the top and let harden.
4. Slice and serve with a dollop of whipped cream.

For Chocolate Ganache Glaze: 

1. Place chopped chocolate in a small bowl. Heat the cream in a small saucepan over medium heat until it begins to gently simmer. Pour over chocolate, then let sit for 3 minutes.
2. Use a spoon to stir until completely combined and chocolate has melted. It’s ready to pour over the cake right away. If it sets up too much, gently rewarm for a few seconds at half power in the microwave, but be careful–it can burn easily.