Chocolate-Cinnamon Coffee Cake

INGREDIENTS

• ½ cup (1 stick) unsalted butter, room temperature, plus more for pan
• ½ cup blanched hazelnuts, chopped
• 2 ounces bittersweet chocolate, chopped
• ¾ teaspoon ground cinnamon
• 1 cup sugar
• 2 cups all-purpose flour
• ¾ teaspoon baking powder
• ½ teaspoon baking soda
• ¼ teaspoon  salt
• 1 teaspoon vanilla extract
• 2 large eggs
• 1 cup plain whole Greek yogurt