Ingredients

• 1/4 cup unsalted butter room temperature, plus more for baking dish
• 1/2 cup sugar plus 2 tablespoons, divided
• 1 egg plus 1 egg yolk
• 1/2 cup flour
• 1/4 teaspoon salt
• 1/4 teaspoon baking powder
• 1 cup blackberries cut in half
• powdered sugar for dusting
• vanilla bean ice cream