Grind the oats to a flour consistency in a high-speed blender. This takes about 30 seconds.
Place the oat flour in a large glass or stainless steel mixing bowl, such as the bowl for your stand mixer.
Add the yogurt, applesauce, cider/juice or water, sweetener of choice, and all spices to the bowl with the oats and stir until mixed and the oat flour is saturated.
Cover with a tea towel and set aside for at least 8 hours.
When ready to bake, preheat your oven to 350 degrees Fahrenheit and lightly grease a 9" x 13" glass baking dish.
Add the eggs to the soaked mixture and stir (or use your stand mixer) to fully incorporate.
Last, mix in the baking soda and baking powder.
Pour into prepared baking dish.
Bake 45 to 50 minutes or until browned on top. The top should spring back when pressed, and a toothpick inserted should come out clean.
Remove from the oven and serve immediately or store to use for breakfasts or snacks throughout the week.
Store cake in the fridge after 2 days.