- Preheat oven to 350˚F.
- Butter the sides of an 8” springform pan. Line the bottom of the pan with parchment, butter the parchment and dust the inside of the pan with cocoa powder. Knock out any excess cocoa powder.
- In a medium microwave safe bowl, combine butter and chocolate. Heat in 15-20 second increments and stir between until chocolate is melted. Whisk to emulsify chocolate in butter. Allow to cool until warm to the touch.
- In a large bowl whisk together the egg yolks and half of the sugar (½ cup) until well combined.
- Add the rum, vanilla and almond extract and whisk to combine.
- Sift the buckwheat, almond flour and salt into the yolk mixture. Pour in the chocolate mixture and whisk to combine.
- Place the egg white in the bowl of a stand mixer fitted with the whisk. On medium low speed mix until the yolks become foamy.
- Add the remaining 1/2 cup sugar in two additions and then turn the speed up to high and whisk until medium stiff peaks form.
- Carefully fold the egg whites into the chocolate mixture in three additions, taking care not to over mix and to maintain the volume of the whites as much as possible.
- Pour the batter into the prepared springform pan. If using a heart shape pan you will not need all of the batter. For our heart shaped pan, we used approximately two thirds of the batter and made the rest into muffin cups. Lift the pan off of the counter and drop it down to knock out any air bubbles in the batter.
- Place in the oven and bake for 30-35 minutes (25 min for a heart shaped pan) until a toothpick inserted in the middle comes out with very moist crumbs. It is important not to over-bake this. The middle of the cake should still be just a bit wiggly when you take it out.
- As the cake cools the centre will collapse down a bit and the sides will crack. This is supposed to happen.
- Allow the cake to fully cool and chill in the refrigerator.
- To decorate, dust the cake first with a layer of cocoa powder and then a thin layer of icing sugar over that. Garnish with raspberries and drizzle with melted white chocolate.