In a large bowl, add flour, baking powder, salt and whisk well. Then add milk and Greek yogurt, mix well until combined. Dough will be sticky.
Donut maker machine: Preheat and spray with cooking spray. Add enough dough to cover the holes, close and cook until golden brown. Transfer to a plate and proceed with remaining dough.
Oven (donut holes): Preheat oven to 375 F and line large baking sheet with parchment paper. Add a bit more flour to make dough thicker. Using small trigger scoop, scoop some dough, smooth at the bottom and release on baking sheet. To roll with hands, you will have to oil your hands and then roll the balls. This dough is sticky. Bake for 15 or so minutes.
Air fryer (donut holes): Preheat the air fryer to 375 F and spray the basket with cooking spray. Add a bit more flour to make dough thicker. Using small trigger scoop, scoop some dough, smooth at the bottom and release on baking sheet. To roll with hands, you will have to oil your hands and then roll the balls. This dough is sticky. Bake for 12 or so minutes.
On a large plate, add sugar and cinnamon and whisk with a fork. Spray donuts with cooking spray or brush with melted butter and dip in cinnamon sugar coating on both sides or roll. Enjoy!
Notes
Store: Donuts taste best same day. Store under a linen towel for first 24 hours. I doubt you will have nay left but if you do, keep them in an airtight container for 2 more days. After that freeze them.
Freeze: In an airtight container or Ziploc bag for up to 3 months. Thaw on a counter for an hour or so. Reheat in a microwave or air fryer for a few minutes.