Scald the milk in a small saucepan over medium heat until you see steam rising up over the surface. Remove from the heat, add ½ cup sugar and stir to dissolve. Allow to cool until it feels warm to touch (see note).
While the milk is cooling, mix the yeast with ½ teaspoon sugar and the warm water in a small bowl. Allow to stand 10 minutes until frothy and bubbly.
In a stand mixer bowl, place the flour, salt, egg, egg yolk, butter, warm milk and yeast/water mixture. Attach the flat beat and mix slowly until ingredients are incorporated. Increase speed and beat for 5 minutes until dough is smooth. Switch to a dough hook and knead for a further 3 minutes. It is correct for the dough to be soft but not excessively sticky. Add a little more flour if it is too sticky. I didn't need any extra flour.
Wash and dry the bowl and coat it with a little oil. Form the dough into a ball and turn it around in the bowl until all sides are coated with a little oil. Cover with plastic wrap and set in a warm place to rise for 2 hours or until it triples in volume.
Deflate the dough and form into a ball again. Cover with plastic and allow the dough to rise a second time for 1 hour or until it doubles in volume.
To shape the dough
Pat the dough into an 8 inch (20cm) square. Cut 8 strips across then cut 8 strips down making 64 even pieces. Roll each into a rough ball.
Prepare a two piece angel food pan by coating well with cooking spray. Have the melted butter in a small bowl and mix the sugar and cinnamon together on a large plate.
Assemble the cake
Put a few ball of dough into the butter, use a spoon to turn them around to be well coated with butter. Remove each piece with a spoon, draining the butter back into the bowl then toss the butter coated balls in the cinnamon sugar.
Arrange the balls evenly in the base of the prepared pan. Continue with of the balls of dough until all coated and arranged in the pan.
Cover the pan with plastic wrap and allow to rise for 1 ½ to 2 hours.
In the meantime, preheat the oven to 350ºF/180ºC ensuring the racks are adjusted to accommodate the pan.
Remove the plastic wrap. Put the pan in the oven and bake for 50-60 minutes or until a skewer inserted in the cake comes out clean.
Allow to stand for 5 minutes then turn out onto a wire rack to cool. Don't leave the cake too long in the pan as the sugar will harden and make the cake impossible to remove.
Note: Greg Patent states temperature of water and milk for this recipes be 105F-115F (40C-45C). When I checked this temperature it seemed quite a lot hotter than I had used in the past. The hot water directly from the tap did not reach this temperature. I used a slightly lower temperature with no problems but then again I live in a hot climate. The important thing is not to exceed 115F/45C when you are adding yeast directly to water or you will risk killing the yeast.