Baked Banana Donuts with Caramelized Banana Topping

Ingredients

• 1 ⅔ cup all-purpose flour (see notes for measuring)
• 3/4 tsp ground cinnamon
• ¾ teaspoon baking powder
• ¼ teaspoon baking soda
• ¼ teaspoon fine sea salt
• ¾ cup buttermilk, room temperature
• 4 tbsp unsalted butter, melted
• ½ cup mashed ripe banana
• ¼ cup granulated sugar
• ¼ cup dark brown sugar, packed
• 2 tbsp sour cream, room temperature
• 2 tbsp canola oil
• 2 teaspoons vanilla extract
• 1/2 cup brown sugar
• 4 tbsp unsalted butter
• 2 ½ tbsp milk
• 1 cup powdered sugar
• 2 tsp vanilla extract
• ½ tbsp unsalted butter
• 2 tbsp dark brown sugar, packed
• ¼ tsp ground cinnamon
• 1-2 medium fresh bananas, sliced into ½ inch pieces