Preheat oven to 350 degrees. Bake the donut holes according to package directions.
Toss the donut holes in 1/2 of the cinnamon sugar packet that comes in the box. Reserve the remaining cinnamon sugar for later use.
Coat a 6 cup or larger baking dish (or 9"x9" square pan) with cooking spray.
Cut the donut holes in half and arrange in the pan.
In a medium bowl, whisk together the eggs, milk, maple syrup and vanilla extract.
Pour the egg mixture over the donut holes in the pan. Let sit for at least 20 minutes.
Top with the remaining cinnamon sugar and bake for 30-45 minutes until center is set. Bake time will depend on the size of your baking dish. If the top starts to get overly brown, cover with foil for the remainder of the bake time.
Cut into 8 squares and serve, topped with Greek yogurt and fruit if desired.
Make Ahead Instructions: Bake according to recipe, then cool and cover with foil. Store in fridge for up to 4 days. Cut into squares and microwave for 30 seconds before serving.