Spray a glass oven safe loaf pan well with nonstick spray (make sure it fits into your crock)
In food processor or blender pulse Oreo's until finely ground
Mix Oreo's with 3 tablespoons melted butter and them press firmly into bottom of loaf pan
In skillet over medium heat place 4 tablespoons cold butter
Whisk as they melt until they start to bubble and watch closely as it start to develop little brown flecks
As soon as the butter starts to brown remove from heat and set aside to cool slightly
In mixing bowl using hand mixer or in bowl of stand mixer beat softened cream cheese on medium speed for 2-3 minutes until creamy
Add sugar, sour cream and egg to cream cheese and beat for 1 more minute until combined (but do not overmix)
Pour 1/3 of the cheesecake mixture into a separate bowl and add the cooled (but not solidified) browned butter and mix until combined
In the remaining 2/3 of cheesecake mixture add 1/2 cup pumpkin and pinch of spice and mix until combined
Pour the pumpkin cheesecake mixture into the loaf pan on top of the Oreo's to form the bottom layer
Next top with the browned butter cheesecake mixture to form the top layer
Place pan in crock and add water around the outside of the loaf pan high enough to cover the cheesecake mixture (but don't go over the top of the loaf pan)
Cover and cook on high for 2-3 hours until center is set
Notes
I used a glass loaf pan in my 5 quart oval crock and cooked this on high for 2 1/2 hours