Chocolate Pistachio Cake

Ingredients

• 1 1/2 cups plus 1 tbsp all-purpose flour
• 6 tbsps unsweetened cocoa
• 1 tsp baking soda
• 1 tsp salt
• 4 oz butter plus extra for coating the pan
• 2 oz unsweetened chocolate, broken into 1/2 oz pieces
• 1 cup sugar
• 2 eggs
• 1 tsp vanilla extract
• 1 tsp red raspberry vinegar
• 1 cup water
• this amount was just enough for the 4-layer cake
• 8 oz egg whites
• 16 oz sugar
• 1 lb butter, room temperature
• 2 tsp vanilla extract
• 1.5 cups shelled pistachios
• 6 tbsps heavy cream
• 4 oz semi-sweet chocolate, chopped