In a large bowl mix together ricotta cheese, egg, sugar, vanilla extract, and baking powder until combined. Then, add flour and mix together.
Next, dust the working surface liberally with flour and dump the mini donut dough out onto it. Sprinkle more flour over the top of the dough, then using your hands or a floured rolling pin roll or press the dough until it's about 1-inch in thickness.
Using a 3-inch cutter, cut out as many donuts as you can, then collect and press the scraps together and re-roll and cut out more circles. Keep repeating until you have no more dough left. Using a 3/4 inch cookie cutter cut out the centers of each donut.
How to fry the mini donuts:
Preheat a heavy-bottomed pot with about 1-inch of oil until it registers at 375°F. Carefully add some mini donuts and fry them for about 3-4 minutes per side or until they're nice and golden. Once cooked through, remove from the oil onto a cooling rack to cool.
Fill a plastic bag with 1/2 cup of Nutella, snip off the end and drizzle the donuts with Nutella or sprinkle with powdered sugar.