Chocolate & Banana Peel Cake | Reader's Digest Canada

Ingredients

• Peels from 2 very ripe bananas (frozen and thawed, stem and bottom discarded)
• 1/2 cup buttermilk
• 1/2 cup unsalted butter (room temperature)
• 1 + 1/3 cup unsalted butter (room temperature )
• 1 + 1/3 cup white sugar
• 2 large eggs (separated)
• 1 tsp vanilla paste or extract
• 1 + 1/2 cup cake or pastry flour
• 1/4 cup cocoa powder
• 1 tsp baking soda
• 1/4 tsp baking powder
• 1/2 tsp fine-grain sea salt
• 4 large eggs (whites separated and reserved )
• 1 cup white sugar
• 1 + 1/4 cup + 2 tbsp unsalted butter (room temperature, broken into pieces)
• 2 tsp vanilla paste or extract
• 1/4 cup + 1 tbsp smooth peanut butter