In a medium bowl, combine the warm milk and the yeast and mix to combine. Let sit for around ten minutes or until the yeast is nice and active.
Add the butter, powdered sugar, and egg. Mix to combine well.
In a separate bowl, add the 1:1 flour, cornstarch and salt and whisk to combine.
Stir in the dry ingredients to the wet ingredients using a wooden spoon. Stir until well combined.
Cover the bowl with a moist, warm tea towel and let rise for one hour in a warm place. The caramel sauce can be made while the dough is rising if you so desire.
Once the dough has risen for an hour, form the dough into balls roughly 1-½" in diameter. Place the balls on a parchment line baking tray. Cover the dough balls with a moist warm tea towel and let rest for 15 minutes.
Heat the waffle iron and spray with cooking spray.
Place a dough ball on the iron and cook for 90 seconds or until golden.
Remove the waffle from the iron and using a clean, dry kitchen towel to protect your hand from the heat, slice the waffle in half using a serrated kitchen knife. This needs to be done right when the waffle comes off of the iron so that it cuts easily.
Spoon the warm caramel mixture onto one half of the waffle and press the second half down to sandwich the caramel in.
Repeat the process with the rest of the dough balls.