Grease your slow cooker with a little bit of butter or coconut oil.
In a bowl, mix together the sweetener and butter until glossy.
Add eggs, vanilla, pumpkin, and milk until well combined.
Add all of the dry ingredients plus any additional add-ins: oats, pumpkin pie spice, baking powder, and salt.
Pour into greased slow-cooker and cover with lid.
Cook on the low setting for 5 hours. At 5 hours you may think it still looks too wet on top, but turn off the slow cooker and let it sit for 15 minutes. The baked oatmeal reabsorbs any liquid that may have gathered on top and you are left with a very moist, baked oatmeal.