Donut batter:
1 cup all-purpose flour
1 teaspoon baking powder
Dash of salt
¼ cup unsalted butter-melted (½ Tbsp. to grease the pan and 3.5 Tbsp for the dough)
2 ½ Tablespoons sugar
¼ teaspoon cinnamon
1 egg
¾ teaspoon vanilla
7 Tablespoons milk
Filling and Topping:
¾ cup of Nutella (8 oz. or 220 grams)
2 Tablespoons unsalted butter-meted
¼ sugar or light brown sugar
1 teaspoon cinnamon (more or less-to taste)

Instructions