Preheat the oven to 350℉ (180℃).

Spray the donut baking pan well with the cooking spray.

In a medium-sized bowl, mix the flour, baking powder, and salt with a fork until combined. This is your flour mixture; set it aside.

In a large bowl, use an electric mixer to beat the eggs, sugar, and vanilla extract until the mixture is pale and thick.

Melt the butter and let it cool for a few minutes until it reaches room temperature but is still liquid. Then, mix it into the egg and sugar mixture using the electric mixer until combined.

Add half of the flour mixture to the egg mixture. Mix until combined.

Add Greek yogurt and milk, and mix until combined.

Add the remaining flour mixture to the egg mixture, and mix until combined.

Fill each cavity of the donut baking pan ¾ full with the batter. You can use a piping bag or place the batter in a small plastic sandwich bag and cut a small tip off the corner.

Bake the donuts for 15 minutes. Check if they are done by inserting a toothpick into a donut; if it comes out clean, the donuts are ready.

Place the powdered sugar in a mixing bowl.

Add a few drops of food coloring and water.

Mix ingredients with an electric mixer until smooth.

Dip the cooled donuts into the glaze.

Decorate the donuts with rainbow sprinkles and candies.