Heat a medium skillet over medium - high heat. When hot, add the oil, onion, corn, jalapeno, cumin, paprika, and white pepper and cook until the vegetables are soft. Add the seafood stock and simmer briefly, then transfer to a blender. While adding the heavy cream and buttermilk in a slow, steady stream, puree until smooth. Season with salt to taste, then refrigerate until thoroughly chilled.

When ready to serve, ladle into small bowls or cups and garnish with the crabmeat and shaved country ham.