Preheat oven to 180°C / 350°F.
Butter the bottom and sides of a large cast iron skillet.
In the bowl of a stand mixer fitted with the paddle attachment, mix the cold butter pieces with the sugars until well blended, about two minutes.
Add the eggs, one at a time. Give the bowl a good scrape down and ensure everything is well combined, then add the vanilla.
Add the baking powder, baking soda, and salt to the wet mix, and mix well.
Add the spelt flour to the wet mix all at once, and blend until just barely combined.
Next add the chocolate chips, dried cherries, and mix until evenly combined. I like to finish the mixing with a wooden spoon.
Press the dough into the prepared cast iron skillet, using your hands (wet hands are good if the dough is sticking to you) to press the dough into an even layer.
Bake for about 25 - 30 minutes. The skillet cookie is done when puffed and golden on top, and still soft in the middle.
Remove from the oven and let rest for about 10 minutes before slicing into it.
Serve in slices, with a glass of milk or a scoop of iced cream handy. Also amazing served warm, and eaten straight from the pan. Enjoy!