In a medium bowl, combine the flour, dry yeast, and caster sugar. Mix well with a spatula, then add the egg yolks.

Gradually add the milk, butter, and olive oil, stirring until the dough begins to come together. Knead the dough gently to form a smooth ball.

Cover the bowl with a kitchen towel and place it in a warm area to rise for about 2 hours, or until the dough has doubled in size.

Once risen, roll out the dough on a floured surface to about ½-inch thickness. Use a round cutter to cut out donut shapes, and a smaller cutter to make holes in the center.

Heat oil in a deep pan or fryer over medium heat. Carefully fry each donut, cooking 1-2 at a time for about 2 minutes per side until golden brown. Transfer to a plate lined with paper towels to cool.

To make the icing, mix powdered sugar with water until smooth.

Pour the glaze over each donut and decorate with pink, orange, and white sprinkles.