In a small bowl, stir together salt, garlic powder, ginger, cinnamon, cloves, red pepper flakes, and black pepper. Rub the seasoning all over the pork and place in the slow cooker.
Pour the water into the slow cooker around the pork. Cover and cook for 8 hours on low.
Remove pork from the slow cooker and let it rest for about 5 minutes.
To make the sauce:
While the pork rests, melt the butter in a small saucepan over medium heat.
Stir in the ginger and garlic.
Add the heavy cream and simmer, stirring until the sauce thickens.
Slice the pork and serve with sauce spooned on top.