Spray the crock of a slow cooker with non-stick cooking spray (smaller one works best here).
Add the milk and cook on high for 30 minutes then stir and switch to low and cook for 2 hours or until mixture is light brown and caramelized, stirring every 30 minutes. Blend with a hand blender for a minute or two if you want the mixture to be smooth (I recommend this step).
Add the vanilla and cream and stir until blended.
Add chocolate chips and stir until melted.
Stir in pecans until well mixed.
Drop onto sheets of parchment paper (a cookie scoop works great for this).